In the spirit of evidence-based reasoning, why don't we look at what happens where political parties are absent or weak? This includes the new Afghanistan parliament, Colombia before 2005, Liberia, the Philippines, the Thai senate, and numerous municipal councils. Some of these forbid parties entirely, some discourage them by using electoral systems such as the single non-transferable vote, others simply have a political culture that frowns upon them. A few of the resulting characteristics may indeed be positive: debate is often vigorous, attention is paid to local concerns, and populist movements can rapidly reach power (though some may see that last one as a negative!) Generally, however, there are a number of problems:

What are elections like? First of all, proportional representation is difficult-to-impossible without parties, which eliminates one potentially fruitful type of political reform. Second, without party organizations to provide guidance as to a candidate's political stance, the "personal vote" predominates. This means a candidate needs extremely strong name recognition and personal financial resources: elected members are much more likely to be former entertainment celebrities, business magnates, leaders of ethnic or religious groups, local crime-lords or warlords, or of course incumbents. Another way to get personal recognition is to take credit for local spending, so candidates' campaigns tend to focus on the pork they'll bring if elected.

What about after the elections? Without a strong parliamentary whip, elected members can vote however they want, which sounds great—but it means that every single vote becomes an exercise in pulling teeth. Each member has an interest in acting recalcitrant in order to receive compensation in exchange for their vote. Governing coalitions end up ideologically incoherent, based mostly on which members are most in need of money for local projects. Since there's no ideological basis for government, changes of prime minister/president can happen either extremely often or extremely rarely, depending mostly on whether or not there are enough goodies to be passed around.

All this talk of weakening parties may show a lack of knowledge about the rest of the world. If you look around, you'll see that other nations, and most scholars, consider American political parties to be quite weak. Most countries with healthier political systems have parties that are perhaps smaller than the Democrats and Republicans, but are much stronger in the sense of having control over their elected members and candidates.

I'd argue that in the USA, we should be strengthening parties. Allow party whips to demand discipline from members, expelling those who will not vote with the rest of the party. Once a party wins Congress, they'll have to actually implement their agenda—no more making promises that are impractical or that they know they can't keep, and then blaming recalcitrant party members for preventing the passage of laws. Now, each party contains multiple opposing factions that proclaim incompatible visions. Instead, parties could decide internally what policies to support, and then the dissidents could just deal with it. Or dissidents could go start their own party, and you'd finally have some real diversity of views. Corporate influence could even fall. After all, it's a lot harder to bribe (I mean, uh, "contribute to the campaign of") an entire party to change their votes than to bribe one or two members.

One of the great recent successes of electoral design was in fact a party-strengthening exercise. In the unrecognized pseudo-country of Somaliland, political organization was nearly absent, and the nascent leaders worried that the new democratic system would become corrupt, based on local warlords and ethnic leaders. So first they held municipal elections across the country, and only the three parties with the highest nationwide total vote in these elections would be allowed to run in the subsequent national elections. Voilà! A new, fragile country developed three ideological, non-ethnic political parties; and while there are still serious problems there, the political system is pretty good for that region of the world.

The one issue I haven't really addressed is "what about the Interwebs!?" True, most of my information is from third world countries, where the Internet is not a serious factor. Non-partisan municipal governments in the West also have the problems I listed though, and have not typically been revolutionized by the Internet. But who knows, perhaps Naheed Nenshi's election in Calgary is the vanguard of a wave of social-network-inspired non-partisan renewal, I guess we'll see!