Breaking down the White House's quid pro quo argument
White House defense lawyer Alan Dershowitz said a presidential quid pro quo to help reelection is not an impeachable offense. Ilya Shapiro, director of the Robert A. Levy Center for Constitutional Studies at the CATO Institute, joins CBSN to talk about the legal standing of Dershowitz's argument and what would happen if senators' vote on calling witnesses results in a tie.