Sen. John McCain (R-Ariz). went on Fox News today to discuss White House e-mails concerning the 2012 attacks on a U.S. diplomatic post and CIA compound in Benghazi, Libya -- e-mails that were released by conservative watchdog organization Judicial Watch on Tuesday. The Benghazi attacks have proved a source of perpetual tension between the Obama administration and Republican lawmakers on Capitol Hill. McCain called the White House's response to the attacks an "obvious cover-up." He also called Ben Rhodes, the deputy national security adviser, a "political hack for Obama reelect."

Sen John McCain (Ariz.) speaks, flanked by fellow Senate Republicans Lindsey O. Graham (S.C.) and Kelly Ayotte (N.H.), at a news conference on Capitol Hill calling for a special committee to investigate the 2012 attack in Benghazi, Libya. (Michael Reynolds/European Pressphoto Agency)

"This is further authentication that this was a political exercise and is now being covered up in order to reelect the president," McCain told "America's Newsroom" co-host Martha MacCallum.

One of the e-mails, obtained by Judicial Watch through a Freedom of Information Act request, was authored by Rhodes. Sent Sept. 14, 2012 — three days after the initial attack — the e-mail laid out goals for Susan E. Rice, the U.S. ambassador to the United Nations at the time, who was scheduled to go on the Sunday shows to address the attacks.

When asked about the e-mails yesterday, White House press secretary Jay Carney called them "irrelevant." 

“This document, as I said, was explicitly not about Benghazi but about the general dynamic in the Arab or in the Muslim world, at the time,” he said at a Tuesday news briefing. “This was part of our effort to explain our views, both as a matter of policy and as a matter of what was happening on the ground with regards to the protests that were underway around the region.”

McCain, who is on the Senate Armed Services Committee, also repeated his calls for a select committee to be formed that would look into the Benghazi attacks. He and Sens. Kelly Ayotte (R-N.H.) and Lindsey O. Graham (R-S.C.) have been the most vocal supporters of a select committee. They released a statement in late March saying: "It is imperative that we learn everything that happened before, during and after the attacks. A Joint Select Committee should be established."