House Speaker Paul Ryan is the clear favorite to win his Wisconsin primary race on Tuesday, but regardless of the outcome the unexpectedly competitive contest serves as a stark reminder of voter concerns about his performance as leader of the GOP-controlled House.  

Challenger and conservative businessman Paul Nehlen has taken the same populist message that Donald Trump used to win the Republican presidential nomination to challenge Ryan in his district.

Several months ago, polls had Ryan leading by as much as 80 percentage points. Polls still indicate a blowout victory sending Ryan to a 10th term -- barring an Eric Cantor-style, poll-defying upset loss -- but Nehlen has closed the margin somewhat, and at the very least drawn national attention to a once-overlooked contest.

Further, that attention has put the spotlight on the criticism Ryan continues to face on Capitol Hill, months after being elected speaker last October. 

Nehlen -- who has campaigned across the state’s 1st Congressional District in a yellow dump truck that reads “Dump Paul Ryan” -- has largely focused on Ryan’s tentative support for the Obama administration’s Trans Pacific Partnership, which critics argue will send more heartland manufacturing jobs overseas.

“Win or lose, this is a win because we’ve cut the head off the globalist snake,” Nehlen spokesman Noel Fritsch told FoxNews.com on Tuesday, arguing that Ryan has “substantially” backed off his support for TPP in recent days. 

Fritsch several days ago dismissed the most recent poll -- by Remington Research Group in which Ryan was up by 66 points -- as a “farce.”

The Ryan campaign has argued essentially every poll has its candidate with a big, double-digit lead and on Tuesday predicted victory.

Ryan also recently received Trump's endorsement -- though the Republican presidential nominee initially withheld it. 

Nehlen has said that delay “sends a clear signal to Wisconsin voters that Ryan is not his preferred candidate in this race.” 

The race has attracted national attention in large part because of the cautionary tale of the 2014 GOP primary in which House Majority Leader Eric Cantor was upset by Tea Party-backed candidate David Brat. Polling showed Brat trailing by about 30 percentage points on that day, but he won. 

In an interview last week with WND/Radio America, Brat said Ryan is much more attentive than Cantor to his district and its voters, but, “It looks like there is going to be a race there.”

Brat said he ran almost exclusively on the illegal immigration issue, which House leadership has yet to resolve and that has now “morphed into the refugee crisis.’

And he argued that Ryan and his team are “not responsive” to debt and deficit issues. 

“Leadership is under a challenge right now from the American people,” Brat said.