The case for instant runoff voting -- two more examples
One test of a good voting system is whether it effectively prevents a candidate to enter the race as a "spoiler." There is probably a technical term for this, but there ought to be a stability of results. If A would beat B in a two-candidate race, the addition of C to the list of candidates shouldn't result in a victory for B. By extension, adding a candidate to an n-candidate race shouldn't hand the election to someone who would have lost the n-candidate race.
Because many jurisdictions don't have any sort of runoff at all, and only a handful use instant runoff voting, we often see elections where the winner is someone who might not have won with fewer candidates in the race. Sometimes the winner is someone who might have lost head-to-head with several of the other candidates, but wins the multi-candidate race because the other candidates split a common core constituency.
Here are two more recent examples.
Yesterday there was a special primary election in Ohio's 2nd congressional district, a seat previously held by Rob Portman, who is now U. S. Trade Representative in President Bush's cabinet.
Here's the final result (PDF) in the Republican primary:
JEAN SCHMIDT 14232 31.35%
BOB MCEWEN 11565 25.48%
TOM BRINKMAN, JR. 9211 20.29%
PAT DEWINE 5455 12.02%
ERIC MINAMYER 2111 4.65%
PETER A. FOSSETT 1026 2.26%
TOM BEMMES 695 1.53%
JEFF MORGAN 400 0.88%
DAVID R. SMITH 374 0.82%
STEVE AUSTIN 221 0.49%
DOUGLAS E. MINK 100 0.22%
Ohio has no primary runoff, so Schmidt wins the primary despite the 69% of the vote against her.
Had the 4th through 11th place candidates not been in the race, the distribution of their votes to the top three could have put any of the top three in first place. Even an Oklahoma-style primary runoff wouldn't fix the problem, as the top three were close enough that we can't know which of them would have finished 1-2 if the other eight candidates had not been in the race. Instant runoff voting would have produced a winner with the support of a majority of the voters. The beauty of instant runoff voting is that you eliminate the spoiler effect of an additional candidate.
We had another example in last week's Republican primary for New Jersey governor.
Doug Forrester 108,090 35.94%
Bret Schundler 93,926 31.23%
John Murphy 33,662 11.19%
Steven Lonegan 24,346 8.10%
Robert Schroeder 16,691 5.55%
Paul DiGaetano 16,551 5.50%
Todd Caliguire 7,472 2.48%
It's been argued that Steven Lonegan acted as a spoiler for Bret Schundler, peeling off enough conservative support to keep him from once again winning the GOP nomination. The counter-argument is that if the other minor candidates had not been in the race, most of their votes would have gone to Forrester. A runoff is the only way to know for sure.
A simple two-candidate runoff probably would have been sufficient to provide a clear outcome, but theoretically Murphy could have finished second in a three-way race -- the bottom four candidates had enough combined votes that if they had been out of the race and all their votes had gone to Murphy, Murphy would have finished second.