In an escalating war of words over the administration’s handling of the deadly Sept. 11 attack in Benghazi, Sen. Lindsey Graham (R-S.C.) said Wednesday President Obama had “failed as Commander in Chief before, during, and after the attack” and reiterated he would not support a cabinet post for “anyone who is up to their eyeballs in the Benghazi debacle.”

Graham was responding to the president’s robust defense of Ambassador to the U.N. Susan Rice, viewed as a strong prospect for Obama’s second-term secretary of state, who is in Republican senators’ crosshairs over the Benghazi affair.

Senate Armed Services Committee ranking member Sen. John McCain (R-Ariz.) and members Graham and Sen. Kelly Ayotte (R-N.H.) want a Senate select committee of the kind that investigated Watergate to probe the attack, which cost the lives of U.S. ambassador Chris Stevens and three other Americans.