Maine ranked-choice voting as a case of electoral-system change
Jack Santucci
June 29, 2018
Forthcoming in Representation.
Abstract
Ranked-choice voting (RCV) manufactures an electoral majority in a fragmented candidate field.
For RCV to pass at referendum, part of a reform coalition must be willing to lose election to theother part of that coalition, typically an out-of-power major party. A common enemy enables thissort of coalition by assuring (a) the out-of-power party of sufficient transfer votes to win and (b)a winner that junior reform partners prefer to the incumbent. I test this logic against the November 2016 adoption of RCV in Maine. First, I show that the most recent, runner-up party
overwhelmingly supplied votes to the “yes” side. I also show elite endorsements tending to comefrom this party, albeit not exclusively. Then I show a drift in the mass of public opinion, such thatreform partners could coordinate. RCV is likely to find favor where voter preferences are polarized and lopsided, and where multiple candidates split the larger ideological bloc.

The voters of Maine have scrapped plurality elections. In November 2016, by a referendum vote of 52 to 48 percent, Question 5 established single-winner ranked-choice voting (RCV)for party primaries, all state offices, and Congress.1 Though a coalition of the Republican Partyand eleven Democratic state legislators tried to repeal RCV in late 2017, a second ballot initiative in June 2018 reaffirmed the 2016 result.2 Activists in other states hope to follow suit.
As its advocates point out, RCV lets the voter support a trailing candidate without harming their preferred frontrunner. That is because the ranked-choice system manufactures a majority. Voters rank candidates in order of preference. If no candidate has a majority of first-placevotes, the candidate with fewest is eliminated, and ballots for that candidate flow to the nextranked candidates on each. This process repeats until the winner is found.3
Maine’s adoption was the United States’ first significant, statewide enactment of a preferential voting rule. Notwithstanding some isolated and legislatively mandated uses,4 all otheradoptions have been in cities or for statewide party primaries during the Progressive Era (Richie
2004). The only other modern, statewide referendum failed: a 2002 initiative in Alaska (Reilly2004).

1 Other names for RCV are “instant runoﬀ voting” and the “alternative vote.” RCV also may re -fer to the single transferable vote, a candidate-based form of proportional representation. This
article uses “RCV” to refer to the single-winner, majoritarian form.
2 An advisory decision by the Maine Supreme Judicial Court in May 2017 held that RCV could

not be used to elect the Governor. This decision was based on interpretation of state-constitutional language mandating that the Governor win with “a plurality of votes.”
3 Technically, the winner has a majority of ballots that remain in the final round of counting. Ifmany voters have not used all available rankings, that majority may not be a majority of all ballots cast (Burnett and Kogan 2015).
4 RCV is used in some states for military and overseas voters. In 2010, it was used to fill a

North Carolina judicial vacancy, then summarily repealed.

According to conventional wisdom, two big factors shaped the Maine reform coalition.
One is the state’s persistent third-party voting, in spite of its plurality elections. Reformers often
note that nine of the last eleven governors have won with less than 50 percent of votes. As there
had been in Alaska in 2002, Maine has had what some would call a “spoiler problem.”
The second big factor is widespread dissatisfaction with Paul LePage, the state’s Republican governor. According to LePage himself, “I was Donald Trump before Donald Trump became popular” (Kruger 2016). In 2010, he won his first primary with 37 percent of votes, thenwon that general election with 38 percent. Although he faced no primary challenge in 2014, 18
percent of Republican voters left that part of the ballot blank. One might say that, while Maine’s
opposition factions cannot agree on who it should be, all would prefer some other governor, andRCV can pick that person.
There is a political-science lesson here on how reform coalitions can take shape. Consistent with existing literature, the repeated failure of Maine’s plurality system to deliver majority
winners can explain RCV’s popularity there in recent years. What galvanized the coalition was ashift in public opinion away from the leadership of the incumbent party. As a result of that shift,a major party saw value in reform, and other groups could join it in view of their common foe.
The paper proceeds as follows. Section 1 gives a brief history of the Maine RCV movement back to 2000, focusing on the reformers’ roles. Section 2 introduces the literature on electoral-system change, pointing to the need for a public-opinion component. Section 3 sketches asimple, informal model of major-party reform support. Section 4 describes my data, methods,
and observable implications. Section 5 presents results. A final section concludes with thoughts
on RCV’s prospects in current, American politics.

1. A brief history of the Maine movement
Beginning in 2001, there were several failed efforts to enact RCV from within government: in 2001, 2003, 2005, 2007, and 2009. Some of these bills died in committee, and others
failed on one or both floors of the state legislature.
The effort to pass RCV by initiative – that is, without consent from incumbent lawmakers– can be traced to 2011. In that year, the city of Portland held its first successful “instant runoff”
election. The winner garnered 27 percent of first-choice votes in a fifteen-candidate race.
Also in 2011, Maine’s League of Women Voters (LWV) completed its three-year study ofalternative election methods. That had grown out of a flurry of interest in electoral reform after
the 2000 US Presidential election. In that election, votes cast for Ralph Nader deprived the Democrat, Al Gore, of a plurality in Florida and an Electoral College majority (Herron and Lewis
2007). Nader’s “spoiler” campaign triggered a series of bill introductions in US states and cities,
most notably San Francisco, which passed “instant runoff” by a ten-point referendum margin in
2002.5 But Maine reformers did not agree on which single-winner method to substitute for plurality. Some opponents made the familiar argument that RCV would confuse voters.6 Others insisted that approval voting would be a better method.7 Having reviewed the literature (Grofman

5 One background condition in San Francisco was the rise of to-be Mayor Gavin Newsom, heir

to Democrat Willie Brown, and widely opposed by self-styled left-wing groups. In 2003, thosegroups coalesced around Green Party candidate Matt Gonzalez in that city’s final election under two-round-runoﬀ rules. The first RCV election was in 2007.
6 But see Neely and McDaniel (2015).
7 But see Nagel (2007).

and Feld 2004; Neely and Cook 2008), the Maine LWV in 2011 endorsed RCV (Maine Leagueof Women Voters 2011).
The effort to force a referendum received a boost in November 2014. That election saw
yet another three-way race for Governor, with LePage winning on 48 percent of votes. The second-placed candidate was Democrat Mike Michaud, with 43 percent. Third-party candidate Elliot Cutler garnered 8 percent, having come in second four years earlier. According to Diane
Russell, a Democratic politician and co-organizer of the Yes on 5 campaign, “The right time [tolaunch the referendum] was 2014, during the second gubernatorial election. That’s when we collected so many signatures.”8 For whatever reason, however, the wider RCV campaign wanted thevote to be in 2016, not 2015 (The Editors 2015).

2. Defensive and offensive models of electoral reform
The literature on electoral-system change is large and growing. I do not attempt to review
all of it here. Generally speaking, there are two big approaches.
The first explains electoral reform as a defensive move by parties and/or lawmakers who
expect to lose control of government and/or their seats. Many scholars have applied that model tothe adoption of proportional representation (PR) in Western democracies, either purely (Rokkan
1970; Boix 1999, 2010; Ahmed 2012) or in tandem with some other factor (Pilon 2013; Leeman

8 Personal communication, Diane Russell, December 4, 2017.

and Mares 2014; Cox et al., Forthcoming).9 Others have used defensive frames to explain historic RCV adoptions in Western Canada (Jansen 2004: 649-54).
A second approach – call it an offensive model – highlights strategic behavior by parties
trying to get power that they either lost or never had (Benoit 2004, 2007). That can involve negotiating with incumbent parties, who may have their own real or perceived interests in reform(Shugart and Wattenberg 2003; Calvo 2009; Renwick 2010). This is how Farrell and McAllister(2005:83) explain the turn to RCV in Australia. Another path involves negotiation between outparties and dissatisfied factions of incumbent parties, which has been one mode of plurality-system abandonment in the United States (Santucci 2017).
While both approaches explain preferences in an ongoing reform process, neither centerson why a process begins in the first place. History is filled with parties that do not try to change
the voting system. Many of these are not in power, and some that are would stand to benefit.
Shugart’s (2008) argument seems helpful here. He shows that, for a sitting government to launcha reform process, the electoral system must be failing to do what an informed person would expect it to do, with respect its effect on the number of parties and/or candidates. In a single-member plurality system, such as the one in Maine, voters will need to be defying Duverger’s “Law.”
That is, they will need to be voting for parties or candidates other than the top two, in spite of
their incentive to vote strategically (Cox 1997). Once that happens, we can expect a disadvantaged, major party to begin or join a reform process (Shugart 2008:14-5).

9 See Andrews and Jackman (2005) for a rejoinder. Blais et al. (2005) and Weaver (2003) fur-thermore note the importance of awareness of and consensus on electoral reform. The LWV,
among other groups, both spread awareness and built consensus in Maine.

Since ballot initiatives have been the major mode of RCV adoption in the US, the rest of
this paper focuses on an offensive reform strategy. In very few cases has RCV come from withingovernment. It certainly did not in Maine.
Why would out-of-power actors join forces in an offensive effort to pass RCV? Thatwould not be a question if the reform were PR voting. By working together to pass PR, out-ofpower groups can raise their joint seat share (Santucci 2017). In contrast, ranked-choice voting
picks just one winner. Like plurality voting, RCV is what reformers call a “winner-take-all system.” All groups cannot benefit, at least from a seat-maximization perspective (Benoit 2004). For
RCV to pass at referendum, something must offset the fact that all of its supporters cannot win.
One possibility is benefit derived from keeping a mutual enemy out of office.

3. Spoiled elections, partisan advantage, and common enemies
I argue that RCV is likely to find favor where three conditions are met: (1) some spoiler
is present; (2) most voters prefer the losing, major party to its main alternative; and (3) the losing, major party knows this.10
Spoiled elections with non-majority winners help reform get onto the agenda. By “reform," I mean ranked-choice voting. I take as given good-government groups that have endorsed
RCV and considered the alternatives (e.g., approval voting, proportional representation). Howthat happens in the first place raises questions about advocacy strategies and power relationships

10 I use “party” interchangeably with “faction.” RCV has had success in some large-population

cities. Politics in these are factional, with widespread knowledge of who is in what faction.
Even in Maine, one could say that prominent, independent politicians are or once were Democrats. These include Senator Angus King since 1993, and Elliot Cutler, once a member of Jimmy
Carter’s Presidential administration.

within reform movements and donor networks. While interesting, these questions are beyond thescope of the paper, which is about reasons for an RCV adoption.
The second condition — that most voters prefer the losing major party to its alternative— constitutes incentives for a referendum coalition to form. Recall that RCV will pick one winner. Therefore, some portion of the referendum coalition will not win seats under the new system. From the would-be-losers’ perspective, having their coalition partners in office must be better than the alternative: spoiled elections in which the other major party wins again.
From the would-be-winners’ perspective, being preferred to the main alternative is an insurance policy. The would-be-winners want to know whether they are likely to win. Given spatial voting, it is the distribution of preferences that determines how winning-minded voters will
use their first, second, and possibly lower rankings strategically – but especially their second
preferences under RCV (Downs 1957, Cox 1997:144). As a shorthand for condition two, consider this preference distribution both lopsided and polarized.
Finally, the losing major party must be aware of the underlying preference distribution.
While this may seem trivial, reformers and politicians both know that it helps to “see the numbers,” i.e., get a sense of what might happen in a reformed system.
At this point, some may wonder why a party would embrace reform without expecting tobenefit over a very long period of time. First, according to Andrews and Jackman (2005), reform
parties often act as if only the most recent election is important. Second, RCV in the US has been
repeal-prone. Recent enactments in Aspen (CO), Burlington (VT), and Pierce County (WA), forexample, lasted just a few years each. Voters in Ann Arbor (MI) used RCV for only one election,in 1975. Going back to the 1910s, both RCV and a ranked-ballot system known as Bucklin vot-ing saw widespread use in cities and state parties, all of which repealed these reforms by the early 1930s (Bucklin 1911; Richie 2004). Passing RCV today far from guarantees its permanence.
In sum, we can expect RCV to find favor when some “spoiler” is present, most votersprefer the losing major party to is chief alternative, and the losing major party knows this. Table
1 summarizes these conditions and gives some concrete examples from the discussion of Maine.
Table 1: Conditions that constitute incentives for RCV adoption.
Condition

Effect on reform process

Example from Maine

Non-majority winners.

Consensus that RCV isneeded.

Decade-long publiceducation campaign, largely
by League of Women Voters.

Lopsided and polarized
electorate favors losing,major party over its
alternative.

Coalition of major party andsome would-be RCV losers
can take shape.

Widespread dissatisfaction
with new leadership of state
Republican Party.

Losing, major party is awareof public sentiment.

Major party has concretereason to join reform
coalition.

Polling and communicationof its results.

4. Hypotheses and methods
This account will stand as one potentially correct explanation for Maine’s RCV adoption
if it can be shown that:
1. The losing major party's voters supported reform.
2. That party had reason to believe that more voters favored it over the other.
3. We can find no similarly positioned party in the time when RCV was a live issue.
4. Voters and/or politicians from some non-advantaged parties also supported reform.

Survey data would be an excellent way to test these hypotheses. Ideally, they would capture attitudes toward RCV, voters’ state-factional affiliations, and their attitudes toward candidates from 2011 (when RCV became a viable reform option) through November 2016, when
RCV won at referendum. Also helpful would be access to the parties’ internal decision-making
with respect to RCV. None of these are available.
What we do have are (a) the relative electoral standings of Maine’s ticket-leading candidates over time, (b) precinct-level returns from the November 2016 election and referendum, (c)biennial survey data on voters’ placements of themselves and several important political actors,(d) newspaper reports of key politicians’ positions on reform, and (e) archived copies of the Yes
on 5 campaign endorsement list.
I use ecological inference (EI) to identify the faction(s) that voted for reform. Technically,
this is a Bayesian implementation (Lau et al. 2007) of the multilevel model proposed by Rosen etal (2001). On the assumption that presidential voting captures party identification (Klar and
Krupnikov 2016), this method helps us answer questions like: “What proportion of Democrats
voted ‘yes’ on RCV? What proportion voted ‘no’?” Precinct-level results for 2016 and otheryears are available on the website of the Maine Secretary of State.
To capture expectations about potential use of second choices, I project voters and candidates into left-right, ideological space. The Cooperative Congressional Election Studies (CCES)
regularly ask respondents to place themselves and politicians along the ideological spectrum(Ansolabehere and Schaffner 2015, 2017a, 2017b). Aldrich and McKelvey (1977) and Hare et al.
(2015) offer a method for using these placements to recover ideal points. Because the CCES includes representative, state-level samples, we can use the implied points to construct the distribu-

tion of left-right ideology in Maine. Finally, by bridging the 2012, 2014, and 2016 CCES waves,
we can estimate the perceived positions of parties, politicians, and voters over very much of theperiod in which RCV was viable.11
Politicians’ reform positions and electoral standings are straightforward to gather. The
former can be found in local newspapers. The latter are available on websites. Finally, over-timeendorsement data can be gotten from archived copies of the Yes on 5 endorsement page, stored
on Archive.org.

5. Discussion of results
Figure 1 tests the party-support hypotheses. Bars reflect the estimated percentage of voters in each group who voted yes (left) and no (right) on RCV. Line segments represent 95-percent Bayesian credible intervals. As expected, about 80 percent of Democrats supported RCV,and about 80 percent of Republicans opposed it. Most Libertarians also supported RCV, amounting to 5.2 percent of the statewide popular vote. There are not enough of the other types of voters(Green Party, other, and blank) to precisely estimate their support.

FIGURE 1 ABOUT HERE: Support for RCV by presidential voting. L=Libertarian Party,
D=Democratic Party, G=Green Party, R=Republican Party.
11 To bridge the estimates, we need to constrain estimates for two parties or politicians. I use

the generic Republican and Democratic Parties, each of which receives more stable ratings
than the only other entity included in all waves, the US Supreme Court. On a 1-7 scale, with 7
being most conservative, respondents’ mean ratings of the Democratic Party were 2.5 (with astandard deviation of 1.4), 2.4 (1.5), and 2.4 (1.4) in 2016, 2014, and 2012, respectively. Republican Party ratings were 5.7 (1.3), 5.8 (1.3), and 5.4 (1.6). For the estimation procedure, I supply
the following constraints: the Democrats at one random value between -1.1 and -0.9, then the
Republicans at a random value between 0.9 and 1.1. See Hare et al. (2015) for details. Traceplots of parameters show that estimation has converged on stable, posterior distributions.

Note that 18 percent of Democrats voted “no,” and 18 percent of Republicans voted“yes.” As of 2017, a small group of Democrats continued to oppose reform, mostly within government. These included 11 state legislators who voted with Republicans in October 2017 to repeal RCV, as well as Democratic appointees to the Maine Supreme Court, who joined Republicans in a May 2017 advisory ruling against RCV’s constitutionality for gubernatorial races. Quiet
Democratic opposition may have been a strategic response to reform’s popularity, in the sensethat reform was becoming associated with the state-party brand (Reed and Thies 2003, Shugart
2008).12 Why these Democrats opposed reform remains unclear. Perhaps they worried about constituency-level effects on their re-election prospects (Mayhew 1974). Another possibility is that
this group has national-level aspirations. So far, national-level party figures have been silent
about RCV, at least in public. All this just reminds that US parties seldom act with absolute cohesion.
On the Republican side, however, a small amount of RCV support is consistent with opposition to the party’s new leadership. Old-line party leaders endorsed RCV on October 12, 2016
(Warren 2016). As of this writing, a video of that press conference no longer appears online. According to a Yes-on-5 campaign email message on that day, all six Republican endorsers wereex-elected officials. One of them, Peter Mills, had lost to Gov. LePage in the 2010 primary. This
group is the party’s embattled, moderate wing.

12 I observed a Democratic gubernatorial debate in Machias (ME) on 19 April 2018. Not one of

the five candidates spoke negatively of RCV. Several claimed to have supported it through thereferendum process at least.

Figure 2 illustrates the link between mass-level referendum voting and party-elite cues
(Smith and Tolbert 2001; Bowler and Donovan 2016). Using the Wayback Machine from
Archive.org, we can see how the Yes on 5 endorsement list evolved.13 Wayback archived the
webpage 11 times between July 25, 2015, and September 2, 2016, when party labels disappeared
from most of it. This figure gives the cumulative ratio of Democratic to Republican endorsements for all archived versions of the page. In October 2015, with referendum petitions filed andthe first endorsements appearing, Democrats outnumber Republicans by six-to-one. More Democrats than Republicans continue to sign on into the spring and summer of 2016, with a notablebump in March 2016, at which point one Republican falls off the list. Into the autumn, Democrats continue to out-endorse Republicans by more than four-to-one.

FIGURE 2 ABOUT HERE: Politicians’ observed, cumulative endorsements of RCV, by self-reported party affiliation.

Figure 3 tests the public-opinion hypotheses. Each curve represents the distribution ofleft-right sentiment in 2012, 2014, or 2016, respectively, anchored by the estimated positions of
the Democratic and Republican Parties. The public favors neither side in 2012. In 2014, the distribution is bimodal, with the bulk of respondents clustered around the Republican Party. Thatrules out 2014 as a time to consolidate major-party support. Republicans had won the governorship regardless, and Democrats could not have expected a different result from RCV. This result
is reversed in 2016, with a bimodal distribution of ideal points that favors the Democratic Party.
13 http://www.rcvmaine.com/endorsements

Only in 2016 were conditions right for an RCV coalition to take shape: an out-of-power major
party preferred to the incumbent one.

FIGURE 3 ABOUT HERE: Implied left-right ideology of survey respondents.

Figure 4 raises our confidence in the quality of the ideal points. It also corroborates thestory that began this paper: the rightward drift of Maine Republicans, led by Gov. LePage. Points
represent the estimated ideological locations of political figures included in the Maine CCES
samples, 2012-16. The estimates make sense. 2012 Democratic Senate Candidate Cynthia Dill
and the generic Democratic Party anchor the left. On the farthest right are the 2014 U.S.
Supreme Court, LePage in 2016, and the 2012 Tea Party. LePage lurches farther right from 201216, consistent with his increasingly manifest conservatism. Moderate Senators Susan Collins (R),
Olympia Snowe (R), and Angus King (I) straddle the middle of the space, regardless of whether
they are measured in 2012, 2014, or 2016.

FIGURE 4 ABOUT HERE: Estimated ideological locations of Maine political figures, as perceived by CCES respondents.

Case history supports the next hypothesis: that a major party should not have joined thereform effort between 2011, when RCV earned League endorsement, and the 2015-6 referendum
cycle. Following the 2010 election, independent candidate Eliot Cutler was the first major politician to endorse reform. He called for either two-round runoffs or a switch to ranked-choice vot-ing (Bell 2010). Again, Cutler had come in second in with 36 percent of votes. LePage had 38
percent, and Democrat Libby Mitchell trailed with 19 percent. Commentators agreed that an
RCV rerun of the 2010 election would have benefitted Cutler, whose “campaign was based on
appealing to the middle of the political spectrum, the wide band of voters who were weary of
Democratic control, but not quite ready for the Tea Party leanings of LePage.” At the time, there
was so little other elite support that, according to one newspaper, “ranked choice voting may be
a good idea, but expect our winner-take-all, minority-rule system — with all its warts — to bearound for a long time to come” (The Editors 2010).
Democrats did not sign on in force until 2015 (Figure 2). Our earliest indication of achanging mind was in 2014, amidst another three-way race, when the Democratic candidate forgovernor said he was “open-minded about the voting reforms Cutler discussed” (Koenig 2014).
It was not until the 2016 cycle, however, that several major Democrats explicitly endorsed RCV
for Maine. One of them was 2004 presidential candidate Howard Dean (2016).
What about elite knowledge of the public’s shifting preferences? As it turns out, Maine’s
Committee for Ranked Choice Voting was doing its own polling in the run-up to the referendum(Schoen 2016). The Committee released top-line summaries of its August 2016 survey to the
Bangor Daily News, which is eastern Maine’s largest newspaper (Shepherd 2016). That survey
included standard questions on demographics and party identification, as well as a battery of
message tests in advance of the vote. While we do not know whether the parties saw these data,
it is possible that they did.14

14 As of this writing, the public cannot access the raw data.

Opinion polling continued in advance of the June 2018 referendum on retaining RCV.
These new polls also asked about voters’ first, second, and lower candidate preferences (Shepherd 2018).

6. Prospects for ranked-choice voting in modern American politics
In some respects, Americans are reliving the Progressive Era. A defining feature of that
period was Theodore Roosevelt’s third-party presidential run in 1912. In refusing to accept theRepublicans’ endorsement of William Howard Taft, Roosevelt split his party’s vote, ushering in
the only Democratic presidency between 1896 and 1932. An immediate consequence was widespread interest in something called “the preferential ballot for insuring election by amajority” (Taylor 1913). Then as now, the ranked-choice system had enjoyed some use in cities,
both in its pure, “Wisconsin-system” form and as a two-ranking variant called “Bucklin voting.”
Then as now, non-majority winners in high-profile elections propelled reform into the spotlight.
Four background conditions also seem to have reappeared in the modern day. One is ahistorically high level of between-party polarization, now so pronounced that scholars can detect
it in mass-level affect toward the opposing party (Mason 2018). A second is within-party disagreement, which manifests as conflict over whom to nominate (Noel 2016). Both increasingly
propel third-party entry, which, like polarization, is correlated with rising inequality (McCarty etal 2007, Tamas 2018). Finally, demographic trends now favor one party’s numeric advantage: theDemocrats (Griffin 2017).
The net effect is a lopsided and polarized distribution of public opinion. As measured inthis paper, each party has a constituency identifying as closer to it than the other, but one con-

stituency is much larger than that of the opposing party. If multiple candidates divide the larger
constituency, such that none of its candidates win, we can expect RCV to find appeal in that ideological bloc. In 1913, when C.F. Taylor wrote the original RCV manifesto, he used precisely
this type of scenario to motivate his pitch. His toy example was a four-way race with three “Progressives” and one “Reactionary.” With respect to the Progressives, he writes: “The preferential
system permitted them to vote first for the man of their choice and then to mass the progressive
field against the common enemy” (61).
For political science, one important lesson is about politicians’ expectations. I have given
circumstantial evidence – survey data on voter preferences, case history, and endorsement
records – that a group with the capacity to make reform mainstream will not do that unless it expects to win elections under it. That information can come from surveys, its precinct captains, oreven just the zeitgeist. Therefore, we should add rapid change in public opinion to the list of“contingent” reform factors: war, revolution, massive scandal, et cetera.
A second lesson is that RCV may require a polarized electorate, at least at the adoption
stage. From the perspective of the junior partner in a reform coalition, RCV requires accepting an
expected, electoral loss. What offsets that loss is disliking the current winner more than one dislikes a senior reform partner. RCV is a winner-take-all rule, like the plurality system it replaces.
My account of Maine suggests two research directions. First, if RCV adoption goes handin-hand with polarization, that may help us understand why it has been unstable in the UnitedStates. When RCV leads to a winner from outside the dominant block, a sufficiently large set ofactors may find reason to repeal it. I look forward to testing that hunch in future work.

Also, there is work to do on RCV in US cities, both now and in the years around the election of 1912. With respect to the Progressive Era, we still lack an authoritative list of what cities
had preferential-majority systems in what years. Chris Hughes documents their use in state andlocal primaries (RCV Resource Center 2017), and the Center for Election Science (n.d.) lists 39
Bucklin adoptions from 1911 through 1917, apparently for public elections. The articles by
Bucklin (1911) and Taylor (1913) suggest more widespread use. These adoptions could be compared with 19 modern, municipal cases. My account of Maine has centered on third parties, butcity politics tend to be single-party and factional. Do Maine-like dynamics obtain in such settings? Taylor’s century-old account of “massing the progressive field” suggests they might.
Ftinally, I point out signs to watch for in states with RCV campaigns. One of those is“spoiler” voting. Four of the most advanced campaigns are in Massachusetts, Minnesota, New
Mexico, and Utah. In 2018, gubernatorial elections in two of these states will feature third-party
candidates. Libertarians are running in Minnesota and New Mexico. The Grassroots-Legalize
Cannabis Party also will field a candidate in Minnesota. Although it has no third-party candidate
this year, Massachusetts has had three-way races in two of its last three elections. In 2014, thethird-party vote share exceeded the margin of victory between the Democratic winner and Republican runner-up. Will third-party entry propel more voting-system change in states? It depends on whether the two-party system, which is globally unique and fairly recent (Shugart
2001, Hirano and Snyder 2008, Eidlin 2016), will continue to hold at the state level.

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Estimated percent in each groupvoting "yes" and "no" on Question 5
100

80

60

40

20

0

Johnson(L)

Clinton
(D)

Stein
(G)

Other

Blank

Left bar = "yes"; right bar = "no"Segments = 95% credible intervals

Trump
(R)

RCV endorsers:
Ratio of Democratic to Republican politicians
6.5
132 D
22 R

6.0

137 D
23 R
150 D
26 R
161 D
29 R

5.5

156 D
153 D 30 R
30 R

5.0

167 D167 D
35 R 35 R

176 D
37 R

197 D
42 R

209 D
45 R

02
20

16

−0

8−

30
20

16

−0

6−

31
5−
−0
16
20

20
1 3−
20 6− 05
16 03
−0 −1
3− 7
25
20
16
20 −0
16 4−
−0 19
4−
30

14

−0
16
20

20

16

−0

2−

27
1−
−1
15
20

20

15

−1

0−

23

4.5

Distributions of respondents' implied ideal points
0.30
2014

2012
2016

0.25

0.15

0.10

0.05

Rep. Party

Dem. Party

Density

0.20

0.00
−3

−2

−1

0

1

Left−right conservatism

2

3

Estimated ideological locationsof Maine political figures
SCOTUS.2014 ●GovLePage.2016 ●TeaParty.2012 ●TedCruz.2014 ●GovLePage.2014 ●GovLePage.2012 ●RandPaul.2014 ●HouCandPoliquin.2016 ●repparty ●HouCandPoliquin.2014 ●SenCandSummers.2012 ●HouCandHolbrook.2016 ●Trump.2016 ●HouCandCourtney.2012 ●Romney.2012 ●HouCandRaye.2012 ●JebBush.2014 ●HouCandMisiuk.2014 ●SenCandCollins.2014 ●TeaParty.2014 ●SenCollins.2016 ●SenCollins.2012 ●SCOTUS.2012 ●SenSnowe.2012 ●SCOTUS.2016 ●SenKing.2014 ●SenKing.2016 ●HouCandMichaud.2012 ●HClinton.2014 ●HouCandCain.2014 ●HouCandCain.2016 ●HouCandPingree.2014 ●SenCandBellows.2014 ●HClinton.2016 ●HouCandPingree.2012 ●Obama.2012 ●Obama.2014 ●Obama.2016 ●HouCandPingree.2016 ●demparty ●SenCandDill.2012 ●

−4

−2

0

Left−right conservatism2