US President Barack Obama laid out a rationale for military intervention against Libyan leader Muammar Gaddafi in a nationally televised address on Monday night.

"Some nations may be able to turn a blind eye to atrocities in other countries," he said. "The United States of America is different."

But in defending his order to launch air strikes on Libya, Obama appeared to be putting forward an argument that contradicts his defense secretary, Robert Gates, who has said the United States has no vital interest in the country.

Al Jazeera's Patty Culhane reports from Fort McNair, Washington.