The U.S. backed a NATO air campaign in Libya earlier this year designed to force Gadhafi out of power.

"The Assad regime should not assume that it can get away indefinitely with mass murder. Gadhafi made that mistake, and it cost him everything,” McCain said, a threat he made two weeks ago in calling for military action against Syria.

McCain has previously held up Gadhafi as the reason “dictators all over the world" should feel nervous. However, McCain has criticized President Obama for allowing NATO to take the lead in the action against Libya. He downplayed the credit the U.S. leadership deserved in Gadhafi’s downfall and subsequent death earlier this month, crediting the British and the French for their leadership instead.

McCain also addressed the potential threat of Iran in Sunday’s speech.

"Their plot to assassinate the Saudi ambassador in Washington has only reminded us of the threat posed by this regime — how it is killing Americans in Iraq and Afghanistan, supporting violent groups across the region, destabilizing Arab countries, propping up the Assad regime, seeking nuclear weapons, and trampling on the dignity of its own people," McCain said.

The Justice Department earlier this month charged two men with conspiring to kill the Saudi ambassador to the U.S. in a bomb plot, alleging the plot was sponsored by officials within the Iranian government.

“No one should test our resolve on this matter,” McCain said. "No issue unifies Americans, and their representatives in Congress, more than the need to protect our friends, our allies, and our interests from the comprehensive threat posed by the Iranian regime.”