Outside groups have spent a record-breaking $45 million in the showdown between U.S. Rep. Tammy Baldwin and former Gov. Tommy Thompson, helping to make the race the most expensive U.S Senate election in Wisconsin history.
Dozens of outside groups have sought to influence one of the most competitive races in the country throughout the course of the campaign, including nine Super PACs, nonprofits and political action committees that have each independently spent more than $1 million, according to data from the Center for Responsive Politics.
Only the U.S. Senate contest in Virginia has seen more third-party spending—about $51 million—than the Baldwin-Thompson race this cycle.
In Wisconsin’s last U.S. Senate race two years ago between Russ Feingold and Ron Johnson, outside spending barely topped $5 million.
Mike McCabe, the director of the campaign finance watchdog group Wisconsin Democracy Campaign, said the influx of outside money in this election is largely due to the landmark 2010 Supreme Court decision Citizens United v. Federal Election Commission, which struck down independent political spending limits for corporations and unions.
“There was certainly a pretty significant campaign arms race before 2010, when the Citizens United ruling came down, but what it’s done is put that arms race on steroids,” McCabe said.
Overall, the amount of spending from both sides has been about even. The biggest spending pro-Baldwin Super PAC is Majority PAC, which has poured over $4.8 million into the race, mostly going towards advertisements attacking Thompson.
Meanwhile, Crossroads GPS, a 501(c)(4) nonprofit organization formed by Republican strategist Karl Rove, has spent over $4.7 million on independent expenditures targeting Baldwin. The group’s Super PAC affiliate, American Crossroads, has also dispensed nearly $2.7 million for the same purpose.
Outside group activity in this race has had an overwhelmingly negative tone, according to the Center for Responsive Politics, as Thompson has been the target of $18.9 million in negative ads compared to $15.6 million in ads against Baldwin.
But McCabe suggested that much of the money outside groups have spent in the closing weeks of the campaign might have been wasted since many voters have already made up their minds. Recent polls show only about three to five percent of the electorate remains undecided in Wisconsin’s Senate race.
“They’re really going after a very narrow sliver of the electorate and yet they’re pumping their messages into the living rooms of all voters and nonvoters as well, and that speaks volumes about how much money they have at their disposal,” McCabe said.
