WASHINGTON Less than three months after his inauguration, President Barack Obama stood before a cheering throng in Prague's historic Hradcany Square and outlined an ambitious vision of a world without nuclear arms.
In remarks recalled later by the Nobel Peace Prize panel, Obama promised to negotiate a new strategic arms treaty with Russia, strengthen safeguards against the spread of nuclear weapons and engage Iran and North Korea to stop proliferation.
"I state clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons," he said to applause.
"This goal will not be reached quickly - perhaps not in my lifetime. It will take patience and persistence."
Three years later, as the president enters the final stretch of his re-election bid, Obama has yet to truly stamp U.S. nuclear policy with his own imprint, experts say.
The document that would define how deeply the United States is prepared to cut back its nuclear arsenal - perhaps to 1,000 warheads or less - and how radically to alter U.S. nuclear doctrine is still awaiting Obama's final approval.
Like other unfinished business, from a federal budget deal to immigration reform, key nuclear weapons decisions apparently have been delayed until after the November 6 election. Arms control advocates fear they might never happen if Obama loses.
A White House spokesman declined comment on the status of the highly classified document, known as the Nuclear Posture Review implementation study.
Obama took office with a major focus on the perils of nuclear proliferation and scored early successes. But after a burst of energy that led to the New START treaty with Russia, measures to strengthen the Non-Proliferation Treaty and a new effort to secure nuclear materials worldwide, the administration's push has flagged in the face of political realities and competing national interests.
His vision of a world without nuclear arms is at best a work in progress.
Republican presidential nominee Mitt Romney has said little during his campaign about U.S. nuclear weapons policy. But his rhetoric on Russia has been harsh, and two years ago he criticized the New START treaty Obama negotiated with Moscow, saying the president had given away too much.
Eliminating nuclear weapons was never going to be easy, but Obama ran into unanticipated difficulties from the outset.
Ordinarily when a president takes office, he issues guidance to the defense secretary on the purpose and use of nuclear weapons. The Pentagon then translates that guidance into detailed military plans, including how many warheads and delivery systems - bombers, ballistic missiles and submarines - it needs. The process takes 18 to 24 months, officials said.
"We didn't have that luxury. When we came into office, we had a number of challenges left on our plate," said a former administration official with insight into the process.
The most pressing was the looming expiration, in December 2009, of the 1991 Strategic Arms Reduction Treaty (START).
START's oversight and verification mechanisms were the foundation for most U.S. insight into what the Russians were doing with their nuclear weapons, and the United States did not want to lose that precious knowledge.
While later treaties have reduced the limits on deployed warheads from 6,000 under START to no more than 2,200, all of them relied upon the verification measures approved in START.
"Every onsite inspection, every piece of telemetry, every visit ... was all based on agreements embodied in START," said the official, speaking on condition of anonymity.
The administration also faced a review conference of the Nuclear Nonproliferation Treaty and needed international cooperation to deal with Iran's nuclear program. Obama and his aides felt all of those issues would be advanced by rapidly replacing the START treaty, the official said.
"So the decision was made very early on in the administration ... that for the New START treaty we would rely on the old Bush administration guidance," the official said. "We would basically swallow hard, even though we wanted to have our own imprint."
With that decision made, things moved quickly.
Three months after the Prague speech, Obama and Russian President Dmitry Medvedev signed a framework agreement to negotiate a new arms treaty that would further cut arsenals of strategic nuclear warheads.
But then talks dragged on. Obama and Russian President Dmitry Medvedev did not sign the New START pact until April 2010, almost a year to the day after his Hradcany Square speech.
The delay foreshadowed the difficulties to come.
"The reason why it took as long as it did is the Russians thought we wanted it more than they did, particularly after Obama got a Nobel Peace Prize for the Prague speech," said Clark Murdock, an expert on nuclear issues at the Center for Strategic and International Studies think tank.
Under the accord, the two sides agreed to reduce their numbers of deployed nuclear warheads to no more than 1,550 within seven years.
The United States, based on the Bush administration guidance, had been prepared to go below the 1,550 figure, the former administration official said, but the Russians resisted.
Even with the higher number, the administration had difficulty winning ratification in the Senate.
Early on, Obama and his aides had been surprised by the poor state of aging U.S. nuclear weapons facilities that manufacture plutonium and uranium components for warheads.
He told his Prague audience he was committed to maintaining a safe, secure and effective U.S. nuclear arsenal as long as the weapons existed. And he committed to investing a substantial amount of money in upgrading the nuclear weapons complex.
During Senate debate over New START, Republican Sen. Jon Kyl wrested a pledge for another $4.1 billion for nuclear modernization, drawing criticism from arms control groups that questioned why Washington would spend more on the nuclear complex when it aimed to eliminate the weapons.
Obama has pledged "as much as $214 billion to modernize that complex as well as the delivery systems, you know the submarines, the bombers and what have you," said Hans Kristensen, director of the nuclear information project at the Federation of American Scientists.
"It's somewhat of a schizophrenic nuclear policy."
Six weeks after the treaty's passage, Obama wrote to the Senate promising to modernize the triad of nuclear delivery systems and "to accelerate to the extent possible" work on the plutonium and uranium production facilities at Los Alamos, New Mexico, and Oak Ridge, Tennessee.
Months later, amid rising Republican pressure to curb government spending, he essentially reneged on the deal, offering budget plans that funded the uranium facility work while pushing the plutonium plant beyond a 10-year planning horizon.
SUCCESSES AND SETBACKS
Obama made significant progress on other nuclear fronts. He won adoption of a plan to strengthen the Nuclear Non-Proliferation Treaty, and stepped up funding and efforts to secure nuclear materials worldwide.
But there were major setbacks as well.
Diplomacy and covert action have failed so far to stop Iran's suspected quest for the bomb, and denuclearization talks with North Korea are in a deep freeze.
Nuclear-armed Pakistan withdrew its backing for talks on a Fissile Materials Cutoff Treaty, effectively blocking negotiations to halt production worldwide of fissile material for nuclear arms.
Obama promised in Prague to aggressively pursue U.S. ratification of the Comprehensive Test Ban Treaty, which prohibits nuclear tests. But there was little chance of getting Senate Republicans to back another arms accord after New START.
Most of Obama's successes in advancing his nuclear agenda occurred during his first two years in office and were, relatively speaking, easy compared with more fundamental arms reductions the president proposed in Prague.
The question remains: How many nuclear warheads, and nuclear bombers, submarines and missiles, does the United States need to achieve its strategic aims, which call for reduced reliance on atomic weapons?
The answers are supposed to come from the Nuclear Posture Review implementation study, which would finally stamp U.S. nuclear policy with Obama's vision.
Retired Marine Corps General James Cartwright, a former head of U.S. Strategic Command and former deputy chairman of the Joint Chiefs of Staff, has argued 900 nuclear warheads in total - both deployed and in storage - is enough for deterrence.
Many observers believe the administration ultimately will settle on a figure of between 900 and 1,000 deployed warheads. Whatever the figure, the decision is Obama's best opportunity to influence U.S. nuclear policy going forward.
"If he is committed to the vision that he outlined in Prague, what he should be doing here is telling the Pentagon that the role of nuclear weapons shall be restricted to deterring nuclear attack on the United States or its allies," said Daryl Kimball, executive director of the Arms Control Association. "To do that we only need a nuclear force in the hundreds of deployed nuclear weapons, not the thousands."
(Reporting By David Alexander; editing by Todd Eastham)