MADISON, Wis., Nov. 8 (UPI) -- In Wisconsin, Sen. Ron Johnson, one of the most vulnerable Republican incumbents in the country, pulled off a huge upset, defeating former Sen. Russ Feingold in a race that could help the GOP retain control of the Senate.
Though once written off, polls showed the race tightening in the final two weeks, with much of Feingold's lead evaporating. The nonpartisan Cook Political report changed its rating of the race from "leans Democratic" to a pure toss-up a week ago.
Johnson's win put the Republicans one seat away from retaining their majority in the Senate.
The new polling prompted a flood of late campaign cash from both parties and several super PACs hoping to sway the outcome of Senate races in their favor.
Johnson was elected in normally blue Wisconsin in the Republican wave of 2010, when he defeated Feingold.
While outside groups have flooded the airwaves in the Badger State with attacks on Feingold's liberal voting record during his Senate term, Johnson has relied mostly on a positive message in the advertising he controls directly.
His rise in the polls coincided with an ad campaign highlighting constituents who got jobs as a result of programs he supported in the Senate and his history as a successful CEO.
While Johnson has at times broke with GOP nominee Donald Trump, the two have since campaigned together in the state.
Feingold is a liberal who initiated the nation's last major campaign finance overhaul in the 2000s. He did so by partnering with GOP Sen. John McCain, to draft the McCain-Feingold campaign finance legislation that put limits on the amount of contributions candidates can accept. The law also required candidates to audibly "approve" all of their campaign ads so voters would know who was responsible for the messages on the airwaves.