A top adviser to the U.S. president on national security issues said Tuesday that persuading North Korea to get rid of its nuclear weapons "is probably a lost cause" and the best Washington can hope for is to cap the capabilities.

Director of National Intelligence James Clapper said that denuclearizing the Korean Peninsula — long the stated U.S. goal — is now a nonstarter for Pyongyang.

"I think the notion of getting the North Koreans to denuclearize is probably a lost cause," Clapper said at the Council on Foreign Relations think tank in New York. "They are not going to do that. That is their ticket to survival."