Incumbent Sen. Tammy Baldwin (D) faced state Sen. Leah Vukmir (R) in the general election for U.S. Senate in Wisconsin on November 6, 2018.

Baldwin is one of ten Democratic senators up for re-election in a state that President Donald Trump (R) won in 2016. By a margin of one point, he became the first Republican presidential nominee to win Wisconsin since 1984. Baldwin was first elected in 2012 by a margin of 6 points.

Election updates

• August 22, 2018: Baldwin led Vukmir within the margin of error, 49 percent to 47 percent, in a Marquette Law School Poll of 601 likely voters. The margin of error was 4.5 percent.

Polls

U.S. Senate election in Wisconsin, General election: Baldwin (D) vs. Vukmir (R)

U.S. Senate election in Wisconsin, General election: Baldwin (D) vs. Nicholson (R)

U.S. Senate election in Wisconsin, Republican primary

Campaign finance

The chart below contains data from financial reports submitted to the Federal Election Commission.

Election history

2016

The race for Wisconsin's U.S. Senate seat was one of nine competitive battleground races in 2016 that helped Republicans maintain control of the Senate. Incumbent Ron Johnson (R) defeated former Senator Russ Feingold (D) and Phil Anderson (L) in the general election on November 8, 2016.

In a rematch of the 2010 election, Johnson topped Feingold for a second time to retain his Senate seat. Johnson, who trailed in the polls for most of the election, was able to tighten the race as Election Day neared by producing ads that showed his personal side. According to The Milwaukee Wisconsin Journal Sentinel, Johnson and his brother Dean, a co-host and the executive producer of the PBS series "Hometime," "brainstormed ideas that would turn into personal and effective ads that showed Johnson in a favorable light.”

As the race grew tighter, Johnson was also able to attack Feingold in the final weeks of the election with the help of national Republicans who initially thought that the seat was a lost cause. When asked about the last minute outside helped, Johnson said, "I wish I would have had the cavalry show up in June, July, August when Feingold was using his little moneymaking machine to out resource me. I guess, better late than never."

Feingold reacted to his loss by saying to supporters, “I didn’t expect this outcome, to be honest with you.” Commenting on his loss and Democratic presidential nominee Hillary Clinton’s, Feingold said that he did not understand what was happening in the country. He said, “I would urge you to be as restrained as you can be as the next steps occur...this could be one the most challenging times in the history of our country.”

Johnson, who defeated Feingold by three percentage points, said that he "was surprised" by his victory margin. In his victory speech, Johnson said, "I believe America has given us a chance, an opportunity to put this nation on the right path. It's exactly what I intend to do."

U.S. Senate, Wisconsin General Election, 2016

Party	Candidate	Vote %	Votes
	Republican	Ron Johnson Incumbent	50.2%	1,479,471
	Democratic	Russ Feingold	46.8%	1,380,335
	Libertarian	Phil Anderson	3%	87,531
	N/A	Write-in	0%	8
Total Votes			2,947,345
Source: Wisconsin Elections Commission

U.S. Senate, Wisconsin Democratic Primary, 2016

Candidate	Vote %	Votes
Russ Feingold	90.2%	303,791
Scott Harbach	9.8%	33,096
Total Votes		336,887
Source: Wisconsin Elections and Ethics Commission

2012

Tammy Baldwin won election to the U.S. Senate in 2012.

U.S. Senate, Wisconsin, General Election, 2012

Party	Candidate	Vote %	Votes
	Democratic	Tammy Baldwin	51.5%	1,547,104
	Republican	Tommy Thompson	45.9%	1,380,126
	Libertarian	Joseph Kexel	2.1%	62,240
	Independent	Nimrod Allen III	0.5%	16,455
	N/A	Write-ins	0%	113
Total Votes			3,006,038
Source: U.S. House Clerk "2012 Election Statistics"

Demographics

Demographic data for Wisconsin

As of July 2017, Wisconsin had a population of approximately 5,800,000 people, with its three largest cities being Milwaukee (pop. est. 600,000), Madison (pop. est. 250,000), and Green Bay (pop. est. 110,000).