Sens. Charles Schumer (D-N.Y.) and Tom Coburn (R-Okla.) discuss terrorism, drones and immigration; Oklahoma governor Mary Fallin talks about tornado-recovery efforts; David Gergen (Harvard University) and Michael Gerson (Washington Post) offer their thoughts on the scandals plaguing the White House; and historian Joseph Persico is interviewed about his book "Roosevelt's Centurions." Also: a panel of weather experts includes Heidi Cullen, Jeffrey Kluger, David Bernard and J. Marshall Shepherd.