A four-day Wisconsin bus tour paid for by the Koch Brothers and starring Joe the Plumber has fizzled to an end in Madison.

The rally, held in Exhibition Hall at the Alliant Energy Center, drew about 600 people, said Matt Seaholm, state director for the sponsoring group, Americans for Prosperity. The turnout was the largest on the 10-city tour, he said.

Meanwhile, thousands of protesters once again surrounded the state Capitol to speak out against Walker’s plan to curtail collective bargaining, though the gathering was considerably smaller than Saturday’s rally of 30,000 or so.