Wisconsin Republican Gov. Scott Walker (right) celebrates his win over Democratic challenger Tom Barrett at Tuesday night's victory party in Waukesha, Wis. Morry Gash/AP hide caption

itoggle caption Morry Gash/AP

Thousands of protesters swarm the Capitol in Madison, Wis., on Wednesday after Republican senators voted to curb collective bargaining rights for some public union workers. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images