Arms treaty would withstand Russian cheating, Pentagon says

James Miller, the Pentagon’s leading authority on nuclear arms, outlined yesterday for the Senate Armed Services Committee how the administration came to this conclusion.

He was challenged by Senator John McCain, Republican of Arizona, who asked in an incredulous tone why the administration bothered to negotiate a deal if cheating is of no consequence.

“Why have a treaty?’’ McCain boomed. “To say that [Russian cheating] has little, if any, effect, then we’ve been wasting a lot of time and money on negotiations.’’

The ability to verify compliance with the treaty is a key point of debate as the Senate considers whether to ratify the deal, which was signed in April by President Obama and President Dmitry Medvedev. Both governments hailed it as a breakthrough in US-Russian relations and a step toward making the world safer.

The treaty, known as New START, would shrink the limit on strategic warheads to 1,550 for each country, down nearly a third from the current ceiling of 2,200. It requires approval by the legislatures of both nations; the Russian Duma is waiting for the US Senate to act first.

Prospects for ratification are considered strong for the treaty, which has drawn wide bipartisan support among think-tank analysts and former top-ranking officials. But Senate approval might not happen until this fall.

Miller told the committee that the size and structure of the US arsenal of strategic nuclear weapons — a triad of submarines, bomber aircraft, and land-based launchers — provide assurance that any Russian cheating would have little military significance.

“Because the United States will retain a diverse triad of strategic forces, any Russian cheating under the treaty would have little effect on the assured second-strike capabilities of US strategic forces,’’ Miller said. He added that he does not believe Russian cheating is likely.

The ability of missile-bearing submarines and bombers to survive any Russian first strike and to deliver a devastating counterstrike, would be “unaffected by even large-scale cheating’’ by the Russians, Miller said. That fact will discourage Russia from trying to secretly exceed the pact’s limits on warheads, he said.

In a crisis the United States would also be able to add extra nuclear warheads to missiles aboard submarines and bombers — a capability the Russians apparently do not have, Miller said.

Although he did not say so in his testimony, Miller’s remarks reflected the conclusions of a classified State Department report to the committee on enforcing the treaty.

Air Force General Kevin P. Chilton, commander of US Strategic Command, which is responsible for ensuring the viability of the nation’s nuclear arsenal, said he agreed with Miller.

“I believe that we are in a good position’’ despite any Russian violations, Chilton said.