John Hostettler is a Republican candidate for the United States Senate in Indiana running against an establishment opponent. He has an anti-Iraq War book and is a former Congressmen.
He doesn't regret the Patriot Act vote. It came up in a debate recently, and I've exchanged emails with him about it. He says he would debate Judge Napolitano on whether or not it's constitutional. But he stands by his votes (both in 2001 and the renewal in 2005).
I think the thing about Hostettler is that he's not a libertarian. But he is a constitutionalist. In my opinion, most of the serious objections to the Patriot Act are on the basis of natural rights arguments more than constitutional ones. And the constitutional arguments against it (including the ones raised by Judge Napolitano) tend to be based, not on what the Constitution itself actually says, but on how judges who view it as a living document have reinterpreted it. Hostettler's really against the living document approach. I would love to see him have that debate with Napolitano. But I'd really like to see him address the Patriot Act more on the basis of basic ethical questions, rather than constitutionality.