Sen. Lindsey Graham, R-S.C., has proposed holding Brennan's nomination until the Obama administration answers more questions about the Sept. 11 attack on the U.S. Consulate in Benghazi, Libya, that killed four Americans, including Ambassador Christopher Stevens.
"The stonewalling on Benghazi by the Obama administration must come to an end," Graham said.
Administration officials initially attributed the attack to the protest of an anti-Islam film that got out of hand. Later, they blamed it on a terrorist attack.
"This ever-changing story should be resolved," Graham said. "It is imperative we understand who changed the talking points just weeks before a presidential election and why."