McCain calls Kerry 'Mr. Secretary,' Kerry responds 'Thank you, Mr. President'

At a press conference urging the ratification of the UN Convention on the Rights of Persons with Disabilities, Sen. John McCain (R-AZ) jokingly referred to his colleague Sen. John Kerry (D-MA) as "Mr. Secretary."

"Thank you very much, Mr. Secretary," McCain said following Kerry's remarks on the treaty.

But Kerry was armed with a comeback. After McCain gave his speech, Kerry took to the podium and said, "Thank you, Mr. President."

"This is what happens when you get two losers up here," he added.

Rumors have swirled that Obama plans to appoint Kerry, the chairman of the Senate Foreign Relations committee, as his next secretary of state or secretary of defense. Republicans have expressed support for Kerry while pummeling another potential nominee, Susan Rice, the U.S. ambassador to the United Nations.

Watch video, courtesy of CBS News, below: