This report is intended to respond to Congress's ongoing interest in campaign finance policy following the Supreme Court's April 2014 McCutcheon decision. The report relies on a question-and-answer format designed to highlight key information in a brief and accessible way. This report offers a preliminary analysis of major policy issues and potential implications that appear to be most relevant as the House and Senate assess the ruling and consider whether or how to respond. The report discusses possible implications of the case for campaign fundraising or disclosure to illustrate policy issues that might be relevant for congressional consideration. This report does not provide a legal analysis of the case or of legal issues that might affect the policy matters discussed here. Other CRS products provide additional information about various policy and legal issues. The parties in McCutcheon and those filing amicus briefs make numerous arguments for and against the existing contribution limits. This report does not attempt to address all those arguments. It also does not address various arguments surrounding legal matters in the case, such as which level of constitutional scrutiny courts should apply or whether courts should defer to Congress to establish contribution limits. This report will be updated to reflect major developments and as policy implications become clearer. McCutcheon v. FEC involves a challenge to the aggregate amount (discussed below) that an individual can contribute to federal candidates, political parties, and political action committees (PACs). During the 2012 election cycle, Alabama donor Shaun McCutcheon wished to contribute more than the existing aggregate limits to candidates and the Republican National Committee (RNC). Prohibited from making and receiving the contributions, McCutcheon and the RNC filed suit against the Federal Election Commission (FEC), which enforces the Federal Election Campaign Act (FECA) contribution limits. In September 2012, a three-judge panel of the U.S. District Court for the District of Columbia upheld the aggregate limits. Through a review process specified in the Bipartisan Campaign Reform Act (BCRA), the case was then appealed to the Supreme Court. On October 8, 2013, the Court heard oral argument. On April 2, 2014, the Court issued a plurality opinion striking down the aggregate limits on constitutional grounds. The decision does not affect base limits (discussed below) that individuals may contribute to particular candidates or parties. Instead, McCutcheon permits individuals to give limited contributions to an unlimited number of candidates, political parties, and political action committees. For example, both before and after McCutcheon , an individual could give a total of $5,200 to a congressional candidate during the 2014 election cycle. After McCutcheon , that individual contributor can contribute to up to $5,200 to as many candidates as he or she chooses. Before the decision, the aggregate limits would have functionally capped the number of candidates, parties, or PACs a contributor could support. FECA, as amended, specifies two different kinds of contribution limits. The first are individual limits . These limits, sometimes also called base limits , place a ceiling on the amount that an individual, party, or PAC can contribute to a single candidate, party, or PAC during a single election. Second, FECA limits the aggregate amount an individual can contribute to all candidates, parties, or PACs. The aggregate limit on individual contributions appears to be most relevant for McCutcheon . Table 1 below summarizes the relevant individual and aggregate limits for 2013-2014. As the table shows, individuals can contribute up to $2,600 per candidate, per election (for a total of $5,200 for both the primary and general elections, or the complete 2014 election cycle); $5,000 annually to PACs; and $32,400 annually to national parties. McCutcheon does not affect these limits. The aggregate limits set overall caps on the amount an individual can contribute. For 2013-2014, pre- McCutcheon , individual contributions could total no more than $123,200. Of that amount, $48,600 could go to candidates, with the remaining $74,600 to parties and PACs. The PAC limits do not apply to super PACs or other political committees (i.e., Carey committees) that can accept unlimited contributions for use in independent expenditures. As Table 1 shows, the plurality decision in McCutcheon invalidated these aggregate limits. Contribution limits have been a hallmark of campaign finance policy and law for decades. Congress established most of the current contribution limits in the 1970s when it enacted and amended FECA. Most recently, Congress updated all but the PAC contribution limits with the 2002 enactment of BCRA. BCRA also adjusted most contribution limits for inflation and reaffirmed congressional support for an overall aggregate limit. Contribution limits are generally justified as a way to avoid real or perceived quid pro quo corruption (e.g., "vote-buying"). Essentially, Congress established the existing individual limits at a threshold at which it believed struck a balance between permitting donors to support their favored candidates while also limiting potential corruption. Support for the aggregate limits generally rests with a concept known as the "anti-circumvention rationale," which holds that an overall limit is necessary to protect the individual limits. Supporters generally argue that if a contributor were permitted to make an unlimited number of contributions, it would make little difference that each individual contribution were capped. Such donors might still enjoy outsized influence in elections and policymaking, therefore potentially corrupting both. Opponents of the aggregate limits contend that the limits cap the amount of political speech or association a contributor can exercise. As CRS has noted elsewhere, appellants (McCutcheon and the RNC) in the case argued that unlike base limits, the aggregate contribution limits act as a spending limit by unconstitutionally restricting the number of candidates, parties, and PACs that an individual can support. More specifically, some contend that the aggregate contribution limits set an arbitrary threshold, beyond which additional contributions allegedly become corrupt. Opponents also generally argue that aggregate contributions, and contributions to parties and PACs generally, carry a lower risk of corruption than contributions to individual candidates. Opponents of the existing limits also suggest that provisions in FECA, FEC regulations, or both already sufficiently protect against circumvention of the individual contribution limits through limits on coordination, coordinated party expenditures, and earmarking. Finally, some contend that limits on contributions to parties force donors to contribute to arguably less-accountable "outside" groups—which are not subject to limits—such as super PACs or 501(c) organizations. It is unclear precisely how the campaign environment, and the need for related legislation or oversight, might be affected by the McCutcheon decision. This section briefly discusses some of the more prominent implications that could arise. Developments thus far suggest that debate will continue about whether existing provisions in law or regulation sufficiently guard against a single contributor amassing potentially corrupting influence or whether new law or regulation is necessary. For some, existing restrictions on earmarking contributions, and the fact that party committees, joint fundraising committees, or PACs are legally separate entities from candidate campaigns, limit the potential for abuse. In fact, the plurality opinion in McCutcheon rejects various hypotheticals involving outsized donor influence as "either illegal under current campaign finance laws or implausible." For others (including the McCutcheon dissenting opinion), aggregate contributions exceeding current limits could violate the spirit of the individual limits and inherently create the potential for corrupting influence. Those favoring additional regulation might also raise concerns about whether larger aggregate contributions could allow candidates to circumvent the base limits by using joint fundraising committees, leadership PACs, or both. Post- McCutcheon , donors may contribute amounts above the previous aggregate limits if they chose to do so. The ability of individual political committees to attract donors who are able to "max out" (as reaching the aggregate threshold is often described) will likely vary considerably. Those who wish to invest large sums in campaigns—albeit through spending rather than contributions—were already permitted to do so pre- McCutcheon by making independent expenditures or contributing to super PACs. Eliminating the cap on aggregate contributions could lead to more money in elections overall, as donors add more contributions to their existing spending. It is also possible that donors will instead reallocate their existing independent spending toward more contributions to candidates, parties, or PACs. Observers have posed a variety of hypothetical scenarios about how donors might react to the opportunity to make unlimited aggregate contributions. To take one example, in the absence of aggregate limits, a donor might give $5,200 to a candidate in every congressional race in the 2014 cycle. That amount could total approximately $2.3 million in House races and $171,600 in Senate contests. The same contributor might also be able to contribute to political party committees, PACs, or both. Various other scenarios have also been proposed, including in Justice Breyer's dissenting opinion. In Justice Breyer's scenarios, using a variety of methods, an individual donor might give as much as $3.6 million to candidates and parties. At least one estimate suggests that a single contributor could give as much as $5.9 million, although this analysis assumes a proliferation of giving to parties and leadership PACs generally not assumed in other estimates. When assessing these and other estimates, it is important to note that they could vary substantially from actual outcomes. Although it is certainly possible that a donor might be able to make a contribution in every race, donors would not necessarily choose to do so, nor would every race be contested. It is unclear how many donors the decision might affect. A 2013 Center for Responsive Politics analysis found that 646 donors gave the maximum permissible amount of $117,000 during the 2012 election cycle. Exact numbers are unknown because existing disclosure requirements do not guarantee that donors who "max out" will be identified. Although political committees must make their best efforts to report to the FEC the name, address, occupation, and employer of contributors who give more than $200, political committees would not necessarily know about a donor's contributions to other political committees.