Kevin Nicholson’s campaign for U.S. Senate received a prominent Wisconsin endorsement on Monday from Jim Klauser, who served as Secretary of Administration under former Governor Tommy Thompson and was considered Thompson’s closest advisor. Klauser is joining the campaign as “Honorary Campaign Chairman.”

The endorsement by Klauser is a possible signal to other Wisconsin conservatives that it’s okay to support the relatively unknown candidate Nicholson who was once a Democrat.

In the press release, Klauser said that Wisconsin needs to vote for Nicholson to “fix this mess in Washington.”

“It’s going to take an outsider with real world experience to enact true conservative change on behalf of our great state,” Klauser said. “I’ve worked with serious leaders in Wisconsin for decades, and I can tell you that Kevin is exactly the right candidate to defeat Tammy Baldwin and get things moving in Washington, DC for the better.”

Nicholson said the addition of Klauser to the campaign was “humbling.”

“He is an incredible leader who knows our state, and knows what matters to the people of Wisconsin,” Nicholson said in the campaign’s press release. “The addition of Jim to our campaign is another sign of our continuing momentum, and I am honored to have his support.”

In the small world of Wisconsin politics, Klauser endorsed former Congressman Mark Neumann in his race for governor in 2010 in the Republican primary against then-County Executive Scott Walker. The Neumann campaign manager in that race was Chip Englander who is now with the Nicholson campaign.

Klauser withdrew his support of Neumann after the campaign against Walker turned negative, and Klauser blasted Neumann in a public letter when the former congressman ran a very negative campaign (also run by Englander) against Thompson in the 2012 Republican Primary for Senate. Part of Klauser’s criticism of Neumann concerned the ad campaign by the national Club for Growth on behalf of Neumann.

“Now, you and your ally, a right-wing Washington D.C. political group is doing the same… trashing, lying, about Tommy Thompson’s record,” the letter said, as reported by the Milwaukee Journal Sentinel. “I understand that several of your former employees are well placed at the ‘Club.’ Evidentially they don’t understand any better than you do Ronald Reagan’s commandment.”

The national Club for Growth has also endorsed Nicholson’s campaign for Senate. They are not affiliated with the Wisconsin Club for Growth.

Ironically, one day after the Nicholson campaign announced Klauser was named, “Honorary Campaign Chairman,” conservative talk show host Dan O’Donnell on WISN-AM reported the national Club for Growth sent out a negative fundraising email calling conservative state Sen. Leah Vukmir (R-Brookfield) a Republican in Name Only, or a RINO.

“Wisconsin offers another conservative vs. RINO primary and a chance to pick up a GOP seat in a swing state,” the Club for Growth email said. “As a US Marine who served in Iraq and Afghanistan and a private businessman, Kevin Nicholson knows a thing or two about making America great. He is running against career politician State Senator Leah Vukmir in the Republican Primary and against progressive Senator Tammy Baldwin in the general.”

O’Donnell objected to the characterization of Vukmir as a RINO. “In truth, Vukmir has been a proven conservative with a sterling voting record in both the State Assembly and State Senate,” O’Donnell wrote on his webpage. “Any assertion that she is merely pretending to be a conservative is not just disingenuous, it is downright dishonest.”

In addition to serving in the legislature, “career politician” Vukmir is a practicing nurse.