Although those who did not make it to the polls in May can vote in today’s party runoff elections, participation is almost certain to fall. In the runoffs held in the most recent presidential year, turnout fell in all 15 runoffs for congressional and state legislative contests. The average decline from the number of votes cast in the primary was almost 54 percent.
Another expectation concerning the runoffs involves the likely outcomes. The candidate who polled a plurality in the primary won two-thirds of the 120 non-local runoffs held since 2004. That level of success is very much in line with previous research. Primary leaders winning about two-thirds of the runoffs has been observed in other states and in elections going back into the 1920s.
The success of the primary leader varies by office. In Georgia since 2014, primary leaders have won eleven of fourteen (79%) of the congressional runoffs. State Senate primary leaders have been less successful winning just over half of thirty runoffs. In contests for the state House, primary leaders won 67% of 42 runoffs.
Going back 50 years, the rate of success for House primary leaders is identical with the primary front runner going on to victory in 192 of 287 contests. The success of state Senate candidates over the long haul is more in line with the two-thirds rule as the primary leader secured the nomination in 63% of 98 contests.
A major factor in whether the primary leader succeeds in the runoff is the size of the margin in the primary. During the last decade when the difference between the runoff contestants was less than five percentage points, the runoff outcome is a toss-up with the leader getting the nomination half the time. In contrast, if the primary leader has at least a 15-point advantage over the runner-up, the leader holds on in 90% of the contests. Similar results exist for the 50-year period. Primary leaders won 54% of 181 contests in which the margin of separation was less than five points. When the leader was 15 or more points ahead, success came in all but 13% of the cases.
The highest profile runoff contest this summer takes place to fill the vacancy created by the retirement of Lynn Westmoreland in the Third Congressional District. In the May vote, Mike Crane led Drew Ferguson by 93 votes or 0.16 percentage points. The original field had seven candidates which resulted in the two who advanced to the runoff each polling just over a quarter of the vote.
Over the last half century when the primary leader barely edged out the leading opponent, gaining a plurality of less than one percentage point, the runoff has not ended well for the plurality winner. In 40 runoffs conducted after such a narrow division in the vote, the primary leader usually lost. In 22 runoffs (55%), the runner-up went on to secure the nomination. In state legislative contests, narrow primary leader lost more often than not winning three of seven Senate runoffs and ten of 22 House second primaries.
The pattern is more promising for congressional frontrunners. In the four closely-divided contests for the US House the primary leader held on to win three times. In 1966 Jack Brinkley, led the primary by a third of a percentage point then polled 57.5% in the runoff. In 2012, Doug Collins led the primary by three-quarters of a point before winning the runoff with 54.6%. Two years later, Jody Hice went from a 0.51 percentage point advantage to 54.3% in the runoff. The one unsuccessful front runner, Amy Tavio, led the 2014 Democratic primary in District 1 by 0.14 points but managed just 36.9% of the runoff vote. All of these contests, like the Third District runoff this year, involved an open seat.
If history provides guideposts for the 2016 runoffs, then most front runners will go on to secure a place on the November ballot. But for those who eked out a narrow plurality, the prospects for the runoff are pretty much a toss-up. Perhaps uncertainty about the outcome will encourage voters, particularly those who will decide the fate of contestants closely matched in the primary, to vote in the runoff.
Charles S. Bullock, III, is the University Professor of Public and International Affairs at the University of Georgia. He is co-author of Runoff Elections in the United States (University of North Carolina Press).
