Senior officials in the Obama administration believe Washington could cut the number of nuclear warheads it deploys by more than a third while still protecting its national interests, according to a report last week by the Center for Public Integrity (CPI), a Washington-based nonprofit specializing in investigative journalism.

White House officials are pushing for a reduction to between 1,000 and 1,100 strategic nuclear warheads, according to the CPI and a report Monday in the New York Times, which said Obama plans to address further nuclear reductions Tuesday in his State of the Union speech to the US Congress.

Those cuts would be even deeper than the some 1,550 deployed warheads allowed by the New Strategic Arms Reduction Treaty (START) that Obama and former Russian President Dmitry Medvedev signed in 2010.

Rather than forging a new treaty or amending the New START deal—both of which would require ratification by the US Senate—Obama is mulling a possible informal agreement with Putin to implement the proposed reductions, the New York Times reported.

Such a “mutual unilateral” agreement on nuclear weapons between Washington and Moscow has a precedent in the 1991 reciprocal withdrawal of thousands of warheads by President George H.W. Bush and Soviet leader Mikhail Gorbachev, said Graham.

“What Obama is proposing to do is something very similar, but under the umbrella of the New START treaty,” said Graham, who worked as a negotiator on numerous US-Soviet arms-control treaties.

There are risks to sidestepping the US Congress when it comes to nuclear reduction efforts, arms control experts said Monday.

“It might be reversed by the next president, either in the United States or in Russia,” William Tobey, former director of counter-proliferation strategy at the White House Security Council under President George W. Bush.

Forging a bilateral treaty with Russia to pursue cuts beyond those mandated by the New START deal would help shield the reduction efforts from future shifts in the political winds, said Tobey, a senior fellow at Harvard University’s Belfer Center for Science and International Affairs.

But securing the needed number of votes could prove difficult for Obama given Republican lawmakers’ considerable resistance to his push for the New START reductions, which the US Senate ultimately approved in a 71-26 vote.

“I think the administration was surprised at how tough it was to get New START ratified,” Steven Pifer, director of the arms control initiative at the Brookings Institution, told RIA Novosti on Monday.

An informal agreement would not be legally binding for either nation, “but if both sides were determined to do it, then that might not be a significant problem,” said Tobey, who participated in START talks with the Soviet Union and in the so-called “Six Party Talks” with North Korea.

If the United States and Russia were to strike such an informal deal, the verification mechanisms in place under the New START agreement could be used to ensure both sides were sticking to their commitment to the additional cuts, said Pifer, a former US ambassador to Ukraine.

Under the New START provisions, the United States and Russia must reduce their respective arsenals to 1,550 deployed warheads by 2018.

Graham, the former top US arms control negotiator, noted that the current talk of reductions only concerns deployment—not whether the removed weapons are going to be retired or eliminated completely.

If the weapons are simply withdrawn under an informal agreement, future leaders in Washington and Moscow—or Obama and Putin themselves—could simply deploy them again unilaterally, Graham said.