Obama enlists big names to push for nuclear treaty

"This is a situation of some national security peril," Lugar told reporters.

Obama and Russian President Dmitry Medvedev signed the pact in Prague in April. Obama met with Medvedev last weekend on the sidelines of an economic meeting in Japan and emphasized his commitment to advancing the treaty during the lame-duck session.

The treaty would reduce U.S. and Russian strategic warheads to 1,550 for each country from the current ceiling of 2,200. It also would set up new procedures to allow both countries to inspect each other's arsenals to verify compliance.

Kerry said there were no substantive disagreements on the treaty itself and that a major objection of Kyl's should have been removed when the administration pledged an additional $4.1 billion for weapons modernization programs.

Earlier Wednesday, Clinton beseeched the Senate to vote this year.

"This is not an issue that can afford to be postponed," the secretary said after the meeting.

Republicans have argued that the treaty would limit U.S. missile defense options and does not provide adequate procedures to verify that Russia is living up to its terms.