MADISON, Wis. -

It may be the only issue where Democrat Russ Feingold agrees with Donald Trump.

In Feingold's quest to return to the Senate, he's joining with Trump, a bipartisan group of office holders and the traditionally solid Democratic base of union workers by loudly voicing his displeasure for a pending free trade agreement known as TPP — the Trans-Pacific Partnership.

Feingold's opponent, Republican Sen. Ron Johnson, won't say whether he's for or against TPP, even though he joined with many other senators in authorizing President Barack Obama to fast-track negotiations.

The issue has particular resonance in Wisconsin, an upper Midwest state that's lost 75,000 jobs since 1993, when the North American Free Trade Agreement took effect. That's based on the number of workers certified for Trade Adjustment Assistance, a federal program that helps those displaced by outsourcing or imports.

Partisan views on free trade deals appear to be shifting in Wisconsin, based on findings of a Marquette University Law School poll done in August. It found that Republicans now take a more negative view of TPP than Democrats do — 48 percent of Republicans say they oppose it while 37 percent of Democrats say they oppose it.

Overall, only 27 percent of registered voters said they supported the deal, the poll found.

Perhaps sensing that sentiment, Feingold is making free trade a key issue of his rematch against Johnson, just as he did in his losing effort in 2010.

Johnson makes his 30-plus years spent helping to build and then lead a plastics manufacturing company in Oshkosh a central theme of his campaign. He emphasizes it in television ads and on the stump, casting himself as a manufacturer and Feingold as a career politician.

But Feingold, in appealing to union members and other longtime supporters, says Johnson needs to make his position clear.

"He won't tell us how he's going to vote on the TPP," Feingold told union members at the AFL-CIO state convention just before Labor Day. "And we have a right to know his position. The TPP is headed straight for us. It's on a collision course. Sen. Johnson, who pretends he hasn't quite figured out what he's going to do with it, you know he's for it. What a joke."

Johnson, who has voted in favor of similar trade deals in the past, said in July he doesn't plan to share his stance before he votes. He said in February that he supports free trade in general because "it does lift all boats" and can create good-paying jobs for Wisconsin workers.

The TPP was meant to forge trade ties between the U.S. and 11 Pacific Rim nations. The agreement would erase most tariffs and other trade barriers among the U.S. and the other nations.

The U.S. Chamber of Commerce, which has endorsed Johnson, supports the deal, as does its state chapter, Wisconsin Manufacturers and Commerce.

"If the U.S. rejects international trade agreements then Wisconsin products will be cut off from the world's most lucrative markets and good-paying jobs will be lost," WMC's president Kurt Bauer wrote recently in the group's publication that is sent to members.

Feingold came out against the TPP in May 2015 after reading a 61-page summary of the agreement posted on the internet by WikiLeaks. Johnson's campaign accuses Feingold of making a snap decision before reading the roughly 6,000-page document.

"Sen. Feingold is a career politician who has never created a job, and now he's jumping to conclusions based on incomplete information — without allowing anyone to give him input on the thousands of pages of the complex deal," said Johnson spokesman Brian Reisinger. "Ron is a manufacturer who is doing the hard work of putting facts before politics. That's why he based his ongoing review on the final version and has been talking with Wisconsin families, farmers, small businesses and all others concerned with how this deal would affect Wisconsin workers."

Wisconsin is one of a handful of states — including Ohio and Michigan — that have suffered from the loss of manufacturing jobs where the TPP is a "very prominent" issue this election, said national AFL-CIO Secretary-Treasurer Liz Shuler, who appeared at the AFL-CIO convention in Madison,

Shuler praised Feingold for being so outspoken in opposing the TPP.

"He's articulating exactly what is on working people's minds," she said.

Mike Bink got a job as a machinist at Master Lock in Milwaukee after graduating high school in 1979. He blames free trade deals like NAFTA for allowing Master Lock and other companies to ship jobs abroad and he worries that the TPP will do the same.

"It'd be very easy for them to remove the rest of our workers," said Bink, who is now president of the UAW Local 469 in Milwaukee. "We do not make a complicated product."

Bink said that in 1999 there were 1,250 workers at Master Lock on Milwaukee's north side. That number had dropped to 225 by 2002 after NAFTA took effect. There are now about 380 workers there, Bink said.

Feingold's opposition to TPP is one of the top reasons Bink said he's supporting him.

"I watched a thousand of my union brothers and sisters, my friends, walk out of that plant," Bink said of Master Lock. "I'm not interested in watching that again."