From the Vault: Battleground Wisconsin

As Wisconsin voters get ready to vote in the recall election of Republican Governor Scott Walker, a look back at how the issue of collective bargaining for public workers sparked outrage in the state. Those embers ignited a divisive electorate 16-months later. Joining Gwen: Martha Raddatz, ABC News; Major Garrett, National Journal; Karen Tumulty, Washington Post; Pete Williams, NBC News.