Romney slammed Craig's alleged behavior Tuesday.

WASHINGTON (CNN) — He was one of Mitt Romney's top backers in the Senate, but the GOP White House hopeful had some harsh words for embattled Idaho Sen. Larry Craig Tuesday.

In an interview with CNBC's "Kudlow and Company," Romney said the Idaho Republican's alleged conduct in an airport bathroom was "very disappointing."

"Once again, we've found people in Washington have not lived up to the level of respect and dignity that we would expect for somebody that gets elected to a position of high influence," Romney added. "He's no longer associated with my campaign, as you can imagine… I'm sorry to see that he has fallen short."

Craig, formerly Romney's Senate co-liaison and head of his Idaho leadership team, resigned his campaign post Monday evening after news surfaced that he was arrested in an airport bathroom for disorderly conduct.

Romney also likened Craig's alleged behavior to that of former Rep. Mark Foley and former President Bill Clinton.

"I think it reminds us of Mark Foley and Bill Clinton," he said. "I think it reminds us of the fact that people who are elected to public office continue to disappoint, and they somehow think that if they vote the right way on issues of significance or they can speak a good game, that we'll just forgive and forget."

"We've seen disappointment in the White House, we've seen it in the Senate, we've seen it in Congress," Romney continued. "And frankly, it's disgusting."

– CNN Ticker Producer Alexander Mooney