Republicans have a steep hill to climb to take control of the U.S. Senate this November. But one of the GOP’s brightest chances to win a Democratic seat is in Delaware. But will Republican voters nominate moderate-to-liberal Rep. Michael Castle or conservative challenger Christine O’Donnell? Why is O’Donnell challenging the establishment favorite? Why does she say Castle is a reliable liberal vote? And how does she respond to the contention that Castle is the only Republican who can win the general election? We talk with Christine O’Donnell.