I can think of a lot of outcomes that would be "catastrophic" if we go in and attack Syria, but the United States having its credibility undermined isn't one of them. I hate to break it to McCain, but that ship has sailed decades ago pal.

McCain: Blocking Obama On Syria Would Be ‘Catastrophic’ For U.S.:

After meeting with President Barack Obama on Monday, Sen. John McCain (R-AZ) said he supports the need to intervene against Bashar al-Assad's Syrian regime over its alleged use of chemical weapons.

He said if Congress votes down the resolution, it would be "catastrophic because it would undermine the credibility of the United States and the president of the United States."

McCain said U.S. credibility would be "shredded" internationally if Congress thwarts a president after he has already committed to military action.

Sen. Lindsey Graham (R-SC), who also took part in the meeting, said he and McCain would like to see a more sustained military effort but that he intended to support the authorization plan that emerges.

Graham said "a pretty solid plan" was emerging from the administration "upgrade the opposition" and to "degrade" Assad's regime. "We don't want endless war... We want sustainable security. And Syria is a cancer that's growing in the region."

"I think they're going to have to work very hard," McCain said, to ensure the resolution passes Congress.

McCain claims he's worried about undermining the President. News to me since that's all he's done for the last five years every time he goes in front of the camera.