Sen. Ron Johnson (R-Wis.) takes part in a sound check on stage at the Republican National Convention in Cleveland. (J. Scott Applewhite/Associated Press)

Sen. Ron Johnson runs down a litany of the United States’ ills: a rising debt and deficit, unsecured borders, threats from the Islamic State. And he knows just what to blame: an overreaching federal government stepping on the throats of American entrepreneurs.

“Sometimes I refer to myself as Mr. Sunshine,” the Wisconsin Republican tells the employees of a small energy-management firm here. “And I do it somewhat facetiously because, let’s face it, I am laying out realities that are not the brightest every now and again.”

Johnson was one of the most unlikely political success stories of the 2010 Republican wave, a plastics manufacturer who made his first run for political office and spent $9 million of his own money in a long-shot bid to unseat popular three-term incumbent Russell Feingold — and succeeded.

Six years later, Johnson is trailing in a rematch with Feingold. Johnson’s sharp-edged message of a nation heading off a cliff hasn’t changed much. But its target has shifted from President Obama to include Democratic presidential nominee Hillary Clinton.

“From my standpoint, you’ve got another six years of failure of liberal progressive Obama-Clinton-Feingold policies,” he said in an interview after his campaign appearance.

Former senator Russ Feingold (D-Wis.) is running to recapture the seat he lost to Ron Johnson in 2010. (Scott Bauer/Associated Press)

As of Labor Day weekend, the unofficial start of the campaign’s final stretch, the electoral map is bigger than Republicans are comfortable with. Bolstered by Republican nominee Donald Trump’s unpopularity with non-white, female and suburban voters, Democrats have recruited candidates in enough Senate and House races to potentially flip control of both chambers.

Democrats’ chances are strongest in the Senate, where they now lead in enough races to eke out a majority, with hopes of putting more in play should Trump continue to falter throughout the fall.

Republicans, playing defense, are asking voters to look past Trump and to question whether they really trust Clinton’s party to fix Washington.

“Wisconsin will need me to be a check and balance on her,” Johnson said when asked about the prospect of a Clinton presidency, before adding that he would “work my tail off trying to find areas agreeing with her as well.”

Johnson is one of dozens of Republicans asking voters to thread that needle, from the suburbs of Philadelphia to the exurbs of central California. After winning his primary last week, for instance, Sen. John McCain (Ariz.) offered his own check-and-balance pitch in a new ad.

In Minnesota, just across the state line here, Democrats’ bullishness about a Trump backlash has them playing in two House districts they would need if they are to retake the House, which remains an uphill fight with two months to go.

In the 2nd District, south and east of St. Paul, the retirement of Rep. John Kline (R-Minn.) has created a race between liberal health-care executive Angie Craig and conservative talk radio host Jason Lewis — a Trump endorser who bested Kline’s preferred successor in the primary. In the 3rd District, south and west of Minneapolis, Democrats recruited state Sen. Terri Bonoff to challenge Rep. Erik Paulsen, who hasn’t faced a credible opponent since his election in 2008.

Paulsen is presenting himself as a can-do Republican who got “the most legislation signed by the president” of anyone in Minnesota’s delegation. He has not endorsed Trump, who has not “earned his support” – and pointedly he does not say what Trump could do to earn it.

“I haven’t been paying attention to him, to be honest,” Paulsen said in an interview at the Minnesota State Fair.

Bonoff, like every Democrat on the ballot this year, can recite Trump’s greatest hits. In an interview, the state senator credited Trump with pulling her into the race after months of pressure from the Democratic Congressional Campaign Committee.

“I was watching those Republican debates in shock,” she said. “My opponent has a record that reflects the current Republican platform, and he’s kind of flown under the radar. He was the co-author of the bill to defund Planned Parenthood, and he has not rejected Trump.”

On Saturday, Bonoff tested her theory of the race by knocking on doors in Paulsen’s hometown of Eden Prairie – focusing on voters who were not identified as Democrats. When the doors creaked open, Bonoff introduced herself as an “exceedingly independent” candidate who had “a 20-year career in business” before running for anything. She mentioned her party only when prompted.

Democrats view the Paulsen-Bonoff race as a reach, one that could be winnable if Trump significantly depresses the suburban Republican vote. They view the Craig-Lewis race as an example of what Trump has already done to the party.

Lewis, a long-time booster of former congresswoman Michele Bachmann, won his primary after years of high-profile talk radio punditry. Craig’s Arkansas twang has not rubbed off since moving to Minnesota; the executive at St. Jude Medical, a Twins City medical device manufacturer, had no political record to run from.

Democrats have attempted to bury Lewis in his old quotes. He’s riffed on single women voting on “the issue of somebody else buying their diaphragm”; suggested it was “hard to say” if the Civil War needed to be fought; and worried about the “cultural suicide” of white people having fewer children than non-whites.

As Craig walked through the state fair more than once, voters told her that they worried about the district if Lewis won. “He says, ‘Oh, I was just trying to be provocative,’ ” Ken Boyd said after shaking Craig’s hand. “We’ve had enough of that.”

Craig, who freely admitted that “both candidates at the top of the ticket are unpopular in the district,” quickly pointed out that her polling had Clinton on top. It was clear, Craig said, that Lewis would be a poor fit.

“Jason has spent his entire career staring at a microphone and trying to elicit the most provocative thought,” she said.

Lewis suggested that Democrats were running on phony issues to distract from Craig’s “radical” agenda and endorsements from liberal groups.

“People are tired of the predictable, canned political campaigns,” Lewis said, as he ordered cups of black coffee from a supporter’s St. Paul restaurant. “I don’t want to be glib about it, but when I see one of those Hillary ads that ends with her and Bill hugging?”

Lewis rolled his eyes and brought up health care, an issue that Democrats aren’t sure how to finesse. As they met voters this weekend, Craig and Bonoff repeatedly met people who had seen insurance premiums spike. A pair of dairy farmers told Craig that their farm’s employees were being forced onto the state’s most expensive plan. A retiree methodically walked Bonoff through all of his cost increases.

“They make an ad about what Trump said 15 years ago,” Lewis said. “Well, great. He said that, but so did my sister at Thanksgiving last year. Meanwhile, people are watching their insurance premiums double. It’s like a bad Miller Lite commercial – less coverage, now with more cost. How is any of this helping with that?”

In Wisconsin, Feingold is running a conventional Democratic campaign, talking about the same kinds of middle-class economic issues that Clinton has embraced. Issues he built his reputation on in his three Senate terms — campaign finance reform, civil liberties and foreign policy in Africa — are not on his front burner.

“I think in 2010 everybody was feeling the pinch; everybody was frustrated that the economy had collapsed,” Feingold said in an interview. “There was a lot of anger. I wouldn’t characterize what I’m seeing right now as so much anger as, ‘Where’s the fairness? Why is it that things have gotten better in some respects, but why am I not feeling it?’ ”

Feingold has taken a cautious approach to questions about Clinton’s honesty. Asked whether the Bill, Hillary and Chelsea Clinton Foundation ought to shut down to eliminate possible conflicts of interest, Feingold suggested that the Clintons “be as open as possible,” and make sure there’s not “anything out there that’s going to tarnish a new presidency.”

Johnson has had a rougher time dealing with his own presidential nominee, staking out a tricky support-but-not-endorse approach.

“Donald Trump, he’s a business guy, knows how hard business is, knows how much harder government makes it,” Johnson said. “When you talk to his most ardent supporters, if they have any discomfort with his positions, they realize that’s his starting position. A good negotiator doesn’t lay the best deal on the table right off the bat. He’s got the personality and the approach of a negotiator of a businessperson, and that’s not all bad for a president of the United States, okay?”

To the extent that Johnson’s fate is separate from Trump’s, it depends on motivating voters such as J.D. Thorne, a Milwaukee employment lawyer who attended a Kiwanis Club lunch where Feingold spoke. Thorne left the event feeling that Feingold “comes off as anything goes.”

“He’s not as strident,” Thorne said. “Johnson is, and I want him to be. I want him to do something.”

Weigel reported from Minnesota.