Rep. Paul Ryan faces a challenge on his right flank this year from a Delavan businessman seeking to channel anti-establishment anger against the top elected Republican in the country.

Paul Nehlen, 46, is challenging Ryan, for whom he previously campaigned, for the Republican nomination for the 1st Congressional District.

It’s only the second time since 1998 that Ryan 46, of Janesville, has faced a primary opponent, and the first time the opponent is mounting a serious campaign.

In 2014, Ryan easily defeated Jeremy Ryan, a frequent protester against Gov. Scott Walker known for riding a Segway.

Nehlen is senior vice president of operations at Neptune Benson, a water filtration company, and owner of the consulting firm Blue Skies Global.

On his recently launched campaign website, Nehlen criticizes Ryan for his support for international trade deals that “sell out American workers” and for receiving the majority of his campaign funding from outside the 1st District.

“Paul Ryan isn’t representing our district. He’s representing the big businesses and big banks that pour money into his campaign coffers,” Nehlen wrote, calling on supporters “to push back against the Washington machine by challenging and removing the guy who now pulls many of its levers.”

Nehlen filed his campaign papers on April 1 and is officially launching his campaign Saturday with the opening of his headquarters in Kenosha, spokeswoman Kirsten Lombard said.

Ryan’s campaign declined to comment.

Media Trackers reported this week that Nehlen voted in only three elections since 2006, including the June 2012 recall. This week conservative blogger Erick Erickson, credited with originating the #nevertrump movement against Republican presidential front-runner Donald Trump, endorsed Ryan.

“Paul Ryan is the best conservatives can hope for right now in Washington, and he’s a decent person,” Erickson wrote.

Eric Ostermeier, a research associate at the University of Minnesota Humphrey School of Public Affairs, wrote in January that a tea party challenge to Ryan would be a long shot because of the state’s long history of re-electing incumbents to Congress.

Since 1950, he said, only one state House incumbent has lost a primary. In 1976 Republican Glenn Davis lost, after serving 10 terms, to state Sen. Bob Kasten. During that period there were only 51 primary challenges in 290 elections featuring an incumbent.