Backfill: Ron Brownstein's made the McCain/Perot point before. I've blogged Brownstein before. And Brendan Nyhan's unconvincingly and condescendingly attacked Brownstein before. Nyhan does it again today. His big argument is Duverger's Law, which says
"In any election where a single winner is chosen by plurality vote (whoever gets the most votes wins), there is a strong tendency for serious competitors to be reduced to two because people tend to vote strategically."
But why wouldn't McCain have a chance of making it into the top two? It depends on the other candidates, no? If the 2004 race had been Bush vs. Kerry vs. McCain, I'd say Kerry might have been the odd man out. ... P.S.: Nyhan notes Brownstein's admission that an "an independent would need to nearly run the table in battleground states—like Wisconsin and Pennsylvania." Again, that may be true, but why would it necessarily discourage McCain from giving it a shot? He's not young, and this is his chance to make history. Oh, right--he doesn't like the media attention! ... P.P.S.: Nyhan says a third-party candidate could only win in "extraordinary circumstances." And we all know how rare those are! ...
I've been busy and hadn't had a chance to reply, so here goes.
First of all, it's implausible that Kerry would have been the odd man out in 2004. The (flawed) 2004 exit polls show that 37% of the electorate was Democrat, 37% was Republican and 26% was independent. Given the strength of party loyalty, it's hard to imagine McCain -- a conservative, albeit heterodox, Republican -- pushing a Democrat into third place, particularly since it might mean the death of the Democratic Party (ask the Whigs).
The more general point is that it doesn't really depend on the candidates, contrary to what Kaus claims. To even become a viable contender as a third-party candidate, you have to spend tens of millions of dollars to get on the ballot in most or all states, plus you need to compete in the ad wars and develop your own grassroots infrastructure from scratch. The party candidates can just plug into an established infrastructure that qualifies them for ballots, ensures them millions of loyal voters, and turns them out on Election Day. As a result, the relentless winnowing of Duverger's Law (referred to above) means they are almost surely going to be one of the two top candidates. It's certainly possible for a third-party candidate to become one of the top two, but it hasn't happened since Teddy Roosevelt in 1912 (and he was an ex-president), and a third-party candidate hasn't won since Abraham Lincoln in 1860.
In addition, these kinds of matchups almost never happen because good candidates like McCain realize that is almost impossible to win as a third-party candidate and don't run. Why did Colin Powell not run as an independent in 1996? Bob Kerrey? Etc. McCain has obviously considered a third-party candidacy and rejected it, both for electoral and governing reasons. Here he is on what would have happened if he had accepted John Kerry's offer to be his vice presidential nominee: "I would have been a man without a country!" He added, "The Democrats never would have really accepted me, the Republicans would never trust me again." The same principle would apply to an even greater extent if McCain was a third party president (ask Jesse Ventura what it's like to govern without a party supporting you in the legislature).
In fact, rather than trying to run as an independent, a new profile in the New Yorker recounts how McCain supported President Bush in 2000 after losing to him in the primaries, spent much of the 2004 campaign defending him, and now appears to be planning a run for president as a Republican in 2008. Even as the media keeps hyping third parties, it looks like the two party system is more robust than we realize.
PS: Kaus's original post got picked up in the Hotline, which also cited me:
WHITE HOUSE '08: What About A Third Opinion?
Centrist Kausfiles, which along with the Los Angeles Times' Ron Brownstein, has been promoting the idea of an internet-based 3rd party candidacy, on the effect of such a bid by John McCain: "Polls show voters are dissatisfied with both parties, no? Ross Perot got 19 percent of the vote despite being labeled (unfairly or not) as wacky. That's a good base to start with. ... McCain would steal both moderate [GOPers] and moderate Dems. Suddenly the Republicans would too have to worry about the center, in a way they maybe wouldn't if they were just running against a Democrat." Kaus is reacting in part to poli sci grad student Brendan Nyhan, a frequent critic of the "centrist third party fantasy."