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JANESVILLE, Wis. — Donald J. Trump, who has risen to front-runner status in part by channeling anti-establishment rage against Republicans, is kicking off his quest for the support of Wisconsin voters at a rally on Tuesday afternoon in Janesville, House Speaker Paul D. Ryan’s hometown.

Wisconsin, which has seen its middle class hit hard by the decline in manufacturing jobs, could prove fertile ground for Mr. Trump, who has defied Republican orthodoxy by opposing many trade deals, calling for high tariffs against China and railing against countries like Mexico and Japan that he says are taking away American jobs because of such agreements. Mr. Ryan, meanwhile, generally supports free trade.

The issue could be particularly resonant in Janesville, where a General Motors plant once employed roughly 7,000 workers at its peak, but closed in 2009, after its workforce had declined to just 1,200 workers.

The rally comes after Mr. Ryan gave a speech last week that notably did not name Mr. Trump but seemed aimed directly at the New York businessman. In it, he urged Republicans to embrace civility and high-minded policy ideas, rather than the “ugliness” that he said has consumed the 2016 presidential race so far.

Shortly after that speech, Mr. Trump, a self-styled counterpuncher, responded by scheduling his first Wisconsin rally before the primary next Tuesday in Mr. Ryan’s hometown.

Trump Comes to City With History of Job Losses and Racial Tension Janesville, Wis., where Donald J. Trump’s campaign will be holding a rally, has been the site of political and economic upheaval in recent decades. Here is a bit of background.

Mr. Ryan was Mitt Romney’s and his party’s vice-presidential selection in 2012, and his name continues to be floated by party officials as the possible presidential nominee if Mr. Trump fails to secure the 1,237 delegates necessary to win the nomination outright at the Republican National Convention in July. The chairman of the Republican National Committee, Reince Priebus, is also from Wisconsin.

Mr. Trump’s visit comes on the same day that Gov. Scott Walker of Wisconsin endorsed his main Republican rival, Senator Ted Cruz of Texas, on the radio program of Charlie Sykes, a popular conservative host in Milwaukee.

In advance of his trip, Mr. Trump made a series of calls to Wisconsin radio programs on Monday — which carry outsized influence among the state’s Republican primary voters — and engaged in a combative back-and-forth with Mr. Sykes.

Mr. Ryan’s office, in a statement (which again did not mention Mr. Trump by name), said the speaker was excited to welcome presidential hopefuls to his state. Voters in Wisconsin will cast their primary ballots next Tuesday.

“Speaker Ryan is glad Republican candidates are campaigning for president in Wisconsin, including his hometown of Janesville,” Zack Roday, a spokesman for Mr. Ryan, said in a statement. “Wisconsin voters expect to talk with candidates seeking public office and hear their views on the major issues before our nation so they can make an informed decision.”