Who controls US election rules? States and Congress fight for power.

As Americans cast their ballots in primary elections, a battle over who sets the rules is intensifying. Efforts to change voting procedures are moving forward in both state legislatures and the U.S. Congress. CBS News legal contributor Jessica Levinson explains the complex legal framework behind election regulation. The U.S. Constitution gives states the power to run most elections, but Congress can override state laws on federal races. This division of authority is now at the center of political debates across the country.