Nelson Dellis successfully defended his title this past weekend as winner of the 15th USA Memory Championship. Dellis talks about the win and how he trained for the event.

He's been a congressman, a governor, the head of a bank and now he wants to be president. Buddy Roemer of Louisiana was running as a Republican. He's now seeking the nomination of Americans Elect: a new online platform for third-party candidates.

Colorado Attorney General John Suthers is among 26 state attorneys general who have sued the federal government over implementation of the health care law. Former U.S. Solicitor General Walter Dellinger has been a vocal proponent of the law. They offer their views on the law's constitutionality.

The popular MSNBC host talks about her start in broadcasting, her life and her new book Drift: The Unmooring of American Military Power, in which she argues that America's national defense has become disconnected from public oversight.

President Obama and other world leaders are meeting in South Korea to discuss the problem of insecure nuclear material. Matthew Bunn, co-author of a new report on loose nukes and an associate professor at Harvard University's John F. Kennedy School of Government, offers his insight.