Purity tests in politics create friction where none should exist.

Here’s the nut of what Wisconsin State Sen. Steve Nass had to say about the appointment of former Gov. Tommy Thompson as interim president of the UW System:

“If Governor Thompson fights to protect families by preserving the undergraduate tuition freeze, then I will be his ally. If Governor Thompson fights to cut administrative spending and positions, then I will be his ally. If Governor Thompson fights to refocus the UW System on education instead of liberal indoctrination, then I will be his ally.

“However, if the UW System demands higher tuition on families, a massive state taxpayer bailout and adopts window-dressing for reforms, then I will continue to stand with the taxpayers and families of Wisconsin in opposition.”

Well. That summarizes what’s different in the Republican Party today from when Thompson was elected to four terms as governor to lead the party and state.

To win four times—generally by wide margins—Thompson was very popular with Republicans and independents, and at least moderately popular with Democrats. His credibility as a conservative-leaning executive was rock solid. Even so, he kept up a dialogue with everybody and was adept at reaching across the aisle to find common ground and reach important solutions to big problems.

These days, there’s no interest in that kind of leader. The political parties have been captured by their extreme fringes, who demand everyone pass a purity test.

Never mind Ronald Reagan’s famous quote: “The person who agrees with you 80 percent of the time is a friend and an ally, not a 20 percent traitor.”

Here’s what Senator Nass could have said:

“I can’t think of a better choice to provide leadership for the UW System than former Gov. Tommy Thompson. For four terms as Wisconsin’s elected leader he brought sound solutions and visionary judgment to the state, while holding the line on spending and ushering in meaningful reforms. His appeal crossed party lines and built consensus on crucial matters confronting Wisconsin. As governor, he was a do-er, not a poser. I look forward to working with Governor Thompson as he shoulders the task of leading and improving Wisconsin’s world-class university system.”