Why did senators go around the president on Iran?

Aired: 3/10/2015 | 0:09:18 | Clip
What prompted 47 Republican senators to send a letter to the leaders of Iran voicing concern about a potential nuclear deal made without congressional approval? Judy Woodruff gets two views on the GOP showdown with the White House from Sen. John Thune, R-S.D., and Sen. Chris Murphy, D-Ct.