Bombing Arrests and Obama Recommits to Closing GITMO

The latest on the Boston bombing investigation including the arrest of Dzokhar Tsarnaev’s three friends. Also, President Obama renews his commitment to close Guantanamo Bay. Plus, Obama's second-term agenda is being tested by unexpected events. Joining Gwen: Pete Williams, NBC News; Michael Duffy, TIME; Doyle McManus, Los Angeles Times; and Christi Parson of Tribune.