Whatever you might think of it, the Tea Party movement, in all its varied and often bizarre manifestations, is becoming more and more of a factor in American politics. One need only recall the special House election in upstate New York to get a sense of what might be in store for 2010. It is entirely plausible that a number of races could be shaken up by the entrance of Tea Party-backed candidates running outside of the major parties. A recent Rasmussen poll shows that a generic Tea Party candidate beats a generic Republican by 5 points among all voters; and the Tea Party tops both major parties among voters with no party affiliation.
Obviously, the GOP wants to bring these folks squarely into their camp, if for no other reason than that they risk having their establishment candidates booted out of contention, not because a majority of voters in a given state or district prefer the Democrat, but because the Tea Party candidate causes a "split" in the the conservative/right-of-center electorate.
So looking at this from the electoral reformer's standpoint, if there was ever a time for Republicans to get behind instant runoff voting, the time is now. Just as Ralph Nader's 2000 candidacy awakened many progressives into realizing how the current plurality-based system can throw things wildly off-kilter, the rise of the Tea Partiers should likewise jolt Republicans into seeing the flaws in having first-past-the-post single-seat elections, as the first person past the aforementioned post may not be the person who most voters would have preferred. Right now there are 10 Democratic US Senators who have won with less than 50% of the vote, and just as an example, in four of those races, adding the GOP candidate's vote share to the Libertarian candidate's would have surpassed 50%.
Such results have gotten some Republicans interested in IRV. But because of the well-known Nader-Gore split in 2000, a lot of interest in IRV in the 2000's has been in progressive communities and states where Republicans are in the minority and more likely to benefit from splits than hurt them. There local Republicans have often opposed IRV.
But IRV also has its Republican backers; just to name a handful, it's supported by 2008 GOP presidential nominee John McCain and former Illinois congressman John Porter, Rob Richie recently co-authored an op-ed with Republican state senator Bill Herbkersman of South Carolina in support of IRV, and it was endorsed by the Alaska Republican Party for statewide use and is used by the Utah Republican Party to nominate its candidates--so this is hardly a fringey left-wing cause. It's just good common sense.
IRV is the best way we know how to accommodate multi-candidate fields that doesn't wind up electing the candidate most voters oppose. This year, as the Tea Party sets its gaze upon vulnerable elected offices, perhaps Republicans will decide that with first-past-the-post, the post is a lot farther away than it used to be.