Mike Rounds and the biggest U.S. Senate wins

Mike Rounds

Update: Unofficial election results indicate that Rounds was reelected with 65.7% of the vote, placing him fifth all-time among U.S. Senate victories, behind Mundt 1966 and ahead of Daschle 1992.

The 2020 U.S. Senate race in South Dakota has been a quiet affair. U.S. Senator Mike Rounds, a former two-term governor seeking his second term in the Senate, is a heavy favorite against challenger Dan Ahlers, a Democratic former state legislator. Although there has been a dearth of public polling, political forecaster FiveThirtyEight gives Rounds a greater the 99% chance of prevailing, predicting that Rounds will win 63.4% of the vote. Larry Sabato’s Crystal Ball rates the seat as “Safe Republican.”

A Rounds win in the 63% range would place his 2020 candidacy comfortably among the top ten Senate victories in South Dakota history. The biggest win was in 2010, when U.S. Senator John Thune made history as the only South Dakotan to be elected without opposition. Setting aside Thune’s 100% performance, here are the ten best showing in contested Senate races:

YearWinner%Runner-up%
1984Larry Pressler (R)74.5%George Cunningham (D)25.5%
2016John Thune (R)71.8%Jay Williams (D)28.2%
1978Larry Pressler (R)66.8%Don Barnett (D)33.2%
1966Karl Mundt (R)66.3%Donn Wright (D)33.7%
1992Tom Daschle (D)64.9%Charlene Haar (R)32.5%
1950Francis Case (R)63.9%John Engel (D)36.1%
1944Chan Gurney (R)63.9%George Bradshaw (D)36.1%
2008Tim Johnson (D)62.5%Joel Dykstra (R)37.5%
1998Tom Daschle (D)62.1%Ron Schmidt (R)36.4%
1926Peter Norbeck (R)59.5%C. J. Gunderson (D)33.3%

Among these ten winners, eight were incumbents seeking reelection. The two exceptions, Pressler in 1978 and Case in 1950, were popular U.S. House members seeking a first term in the U.S. Senate.

Rounds’ victory in 2014 does not come close to making this list, as he won with 50.4% of the vote. That win was more impressive than it appears, however, because Rounds won in an unusual four-way field, facing Democratic nominee Rick Weiland; former U.S. Senator Larry Pressler, a registered Republican running as an independent; and Gordon Howie, a “Tea Party” Republican running as an independent. Although Rounds won just over half the vote, he bested Weiland, the runner-up, by a margin of 20.9%.