11/21/2013: Wisconsin Supreme Court vacated contempt order against anti-collective bargaining law.

09/13/2013: Wisconsin judge struck down controversial collective bargaining law.

09/09/2013: Indiana judge found right-to-work unconstitutional.

08/15/2013: Michigan appeals court ruled right-to-work law applies to state employees.

01/17/2013: Federal judge dismissed dismissed lawsuit challenging Indiana right-to-work law.

09/30/2012: Federal judge struck down parts of Wisconsin collective bargaining law.

09/05/2012: Federal judge dismissed NLRB challenge to Arizona union election laws.

07/06/2011: Federal judge blocked Idaho anti-union law.

03/31/2011: Ohio legislature passed bill limiting state worker collective bargaining.

12/01/2008: President Bush signed executive order barring union rights for some federal workers.

08/14/2008: Labor groups filed election law complaint against Wal-Mart.

07/25/2008: Federal judge dismissed challenge to Arizona union election laws.

12/31/2006: New year marked enforcement of new labor laws in many states.

07/05/1935: National Labor Relations Act rejected signed into law.

05/01/1794: First US trade union blocked formed.