DETROIT (AP) — Republican Gov. Rick Snyder said a right-to-work law that took effect Thursday is a milestone that will bring jobs to Michigan, while protesters promised to exact revenge at the polls for the contentious measure Snyder signed in December.

"The labor movement has done a lot of great things for our country. It's not about being anti-union in my view. It's about being pro-worker," Snyder told business and government leaders.

The law allows Michigan workers to choose not to financially support unions that bargain on their behalf. It applies to labor contracts that are extended or renewed starting Thursday, so many unionized employees will not be affected until their existing collective bargaining agreements end months or years from now.