Article authored by David E. Sanger and appeared in The New York Times.  Article is courtesy of nytimes.com

WASHINGTON — President Obama will use his State of the Union speech on Tuesday to reinvigorate one of his signature national security objectives — drastically reducing nuclear arsenals around the world — after securing agreement in recent months with the United States military that the American nuclear force can be cut in size by roughly a third.

Mr. Obama, administration officials say, is unlikely to discuss specific numbers in the address, but White House officials are looking at a cut that would take the arsenal of deployed weapons to just above 1,000. Currently there are about 1,700, and the new strategic arms reduction treaty with Russia that passed the Senate at the end of 2009 calls for a limit of roughly 1,550 by 2018.

But Mr. Obama, according to an official who was involved in the deliberations, “believes that we can make pretty radical reductions — and save a lot of money — without compromising American security in the second term. And the Joint Chiefs have signed off on that concept.”

The big question is how to accomplish a reduction that Mr. Obama views as long overdue, considering that Republicans in the Senate opposed even the modest cuts in the new arms reduction treaty, called Start. The White House is loath to negotiate an entirely new treaty with Russia, which would lead to Russian demands for restrictions on American and NATO missile-defense systems in Europe and would reprise a major fight with Republicans in the Senate over ratification.

Instead, Mr. Obama is weighing how to reach an informal agreement with President Vladimir V. Putin of Russia for mutual cuts within the framework of the new Start — but without the need for ratification. Mr. Obama’s national security adviser, Tom Donilon, is planning to travel to Russia next month, officials say, to lay the groundwork for those talks. Mr. Obama and Mr. Putin will hold two summit meetings in the early summer.

Even as he revives a nuclear agenda that has been nearly moribund for two years, Mr. Obama is also expected to try to address new threats.

Within days of the State of the Union address, officials say, he plans to issue a long-anticipated presidential directive on combating cyberattacks aimed at American companies, financial institutions and critical infrastructure like the electric grid. The announcement comes at a moment of heightened attacks from China and, most recently, from Iran.

A lobbying effort by American companies last year defeated a bill in Congress that, in some versions of the legislation, would have required private companies to meet minimum standards of protection and to report attacks to the government. It died over objections that the bill would incur huge new costs and involve the government more deeply into private computer networks.

While Mr. Obama cannot impose the failed bill’s mandates by executive order, he is expected to give companies that control “critical infrastructure” access to an experimental government program that has been aimed at protecting defense contractors. The directive will also require the government to inform industry officials of cyberthreats detected by American intelligence agencies; that, in turn, may create some liability for companies that fail to react to the warnings.

The nuclear reduction plan has been debated inside the administration for two years, and the options have been on Mr. Obama’s desk for months. But the document was left untouched through the presidential election. The president wanted to avoid making the reductions a campaign issue with Mitt Romney, who declared at one point that Russia was now America’s “No. 1 geostrategic foe,” a comment that Mr. Obama later mocked as an indication that Mr. Romney had failed to move beyond the cold war.

Mr. Romney, in turn, leapt on a remark that Mr. Obama intended to make privately to Russia’s then president, Dmitri A. Medvedev. He was picked up by an open microphone telling Mr. Medvedev that “after my election I have more flexibility” on missile defense, which Republicans said was evidence that he was preparing to trade away elements of the arsenal.

Among the most outspoken advocates of a deep cut has been a former vice chairman of the Joint Chiefs of Staff, Gen. James E. Cartwright, whom Mr. Obama continues to turn to on strategic issues. General Cartwright has argued that a reduction to 900 warheads would still guarantee American safety, even if only half of them were deployed at any one time.

“The world has changed, but the current arsenal carries the baggage of the cold war,” General Cartwright said last year. The challenges of North Korea, which is preparing a third nuclear test, and the possibility that Iran will get the bomb pose very different kinds of threats to the United States, and do not require the ability to deliver the kind of huge first strike that was the underlying logic of a large arsenal to face off against the Soviet Union.

“What is it we’re really trying to deter?” General Cartwright asked. “Our current arsenal does not address the threats of the 21st century.”

It is unclear how much money would be saved by the nuclear reduction plan that Mr. Obama is about to endorse; partly that depends on how the cuts are spread among the three elements of America’s nuclear “triad”: land-based missiles in silos, missiles aboard hard-to-find nuclear submarines, and nuclear bombers.

“These cuts don’t require a radical change in the triad, and that makes it politically easier,” said Daryl Kimball, the executive director of the Arms Control Association, which has argued for deep cuts. General Cartwright’s more radical plans, by some estimates, would have saved at least $120 billion over the next two decades.

But Mr. Obama is already moving quietly, officials acknowledge, to explore whether he can scale back a 10-year, $80 billion program to modernize the country’s weapons laboratories.

The White House agreed to the spending on the weapons labs as the price of winning Republican votes on the new Start three years ago, but one senior defense official said late last year that “the environment of looking for cuts in the national security budget makes this an obvious target.”

Mr. Obama’s advisers have said he is unlikely to simply announce American cuts unilaterally, though President George W. Bush took a similar step his first year in office before negotiating a short treaty with Mr. Putin that passed the Senate with little rancor.

Along with the executive order on cybersecurity, the administration plans to try again this year to get comprehensive cyberlegislation passed by Congress.

Last month, Senators Tom Carper, the chairman of the Senate Homeland Security and Governmental Affairs Committee, and Dianne Feinstein, who chairs the Senate Intelligence Committee, introduced a cybersecurity bill similar to the one that administration had hoped to pass in 2012.

“We want to foster notice and we want to foster information-sharing requirements,” Janet Napolitano, the secretary of the Department of Homeland Security, said in a recent interview on the legislation. “We want to take care of some of the nuts and bolts like relaxing Civil Service requirements so we can hire more competitively. Really the things that can’t be done by an executive order.”

Ms. Napolitano said that she hoped it would be a high priority for Congress. But “in the meantime we can’t stand still,” she said.