He was the only Senator who voted against the Patriot Act. He voted against the bailouts, against further fighting in Afghanistan, and he has always voted to protect civil liberties.
But the Tea Party elects a Republican businessman because...they love freedom and liberty. Or something.
To be fair, it's not like it was only tea partiers who elected Johnson. There was a lot of gullible Wisconsinites that bought it as well. Enjoy that sweet freedom Wisconsin.