The two largest teachers’ unions in Michigan have lost one-fifth of their membership since 2012, according to Michigan Capitol Confidential. Michigan Gov. Rick Snyder, a Republican, signed right to work into law in 2012.

The Michigan Education Association has lost more than 23,000 dues-paying members since 2012. In the same time frame, the relatively smaller American Federation of Teachers-Michigan lost more than 4,800 members.