President Obama at American University's School of International Service in Washington in August 2015. Obama's speech, held at the same venue in which President Kennedy delivered his famous 1963 speech on nuclear disarmament, focused on the Iran Nuclear Deal as it was being debated in Congress. Photographer: Pete Marovich/Bloomberg *** Local Caption *** Barack Obama (Pete Marovich/Bloomberg)

A group of nuclear nonproliferation experts gathered in the White House Situation Room last Halloween to talk about how President Obama could still make nuclear security an important part of his legacy.

The timing was coincidental, but the location reflected the sensitivity and gravity of the agenda: loose nuclear material, superpower nuclear arsenals, nuclear terrorism, tensions with Russia and the unpredictability of North Korea. The administration also was hunting for ideas about what might be still doable in the president’s waning days in office.

The muted, closed-door White House meeting was a far cry from the rousing speech Obama delivered on April 5, 2009, before a crowd in Prague’s Hradcany Square. There, a hopeful Obama set high goals for reducing the risk of nuclear weapons. He vowed to shrink the U.S. nuclear arsenal, secure poorly guarded nuclear materials such as uranium and plutonium, convene international nuclear summits, and confront and contain North Korea, which just that morning had tested a long-range missile.

His goal, he said, was “to seek the peace and security of a world without nuclear weapons,” while acknowledging that “this goal will not be reached quickly — perhaps not in my lifetime.”

Seven years later, on the eve of the last of four nuclear summits, Obama’s track record is mixed on the issue that he elevated to a top priority. He has won an agreement to limit Iran’s nuclear program, persuaded about a quarter of the countries with loose nuclear materials to move them off their soil, and signed with Russia a new START treaty that includes new weapons limits.

But in his fiscal 2017 budget, Obama has proposed deep cuts in spending on programs to stop nuclear proliferation while leaving intact military spending on a new generation of weapons. The countries that have not given up stockpiles of nuclear material include the riskiest ones, such as Pakistan and India. And this week’s summit will have a glaringly empty chair, Russia. The world’s other nuclear superpower, amid tensions with the United States, has chosen not to attend.

“Presidents George W. Bush and Obama both noted during their campaigns that the United States and Russia are still postured on what they called a hair trigger,” said former senator Sam Nunn, who sponsored legislation when he was still in the Senate to assist Russia and former Soviet republics secure and destroy nuclear, biological and chemical weapons. “We still have the ability to destroy each other in 30 minutes to an hour’s time. Both of them said they would improve that, and as far as I can tell, neither has.”

“The president has only accomplished a fraction of what he hoped to achieve,” said Joseph Cirincione, president of the Ploughshares Fund. And now, he said, especially after the exhausting talks with Iran, “some of the steam has gone out.”

The White House, which did not reply to a request for comment, will likely argue that its achievements are substantial and that there is still time for more progress. It can use the nuclear summit to highlight improved training for nuclear industry workers, including a Chinese safety center created with U.S. help. The administration can also boast of a Latin American declaration that the continent will be a nuclear-weapons-free zone. Before Obama leaves office, Poland, Australia and Indonesia also might rid themselves of nuclear material.

The summit will also coincide with the arrival of a shipment of plutonium from Japan to the Savannah River storage facility run by the Energy Department, fulfilling a commitment Japan made at the 2014 summit to better safeguard dangerous materials.

But the Obama administration has also fallen short of many expectations.

The military’s weapons: Cirincione laments that “there wasn’t a single nuclear weapons program inherited from the Bush administration that Obama has stopped. In fact, he’s added to them.” He points to new land-based ballistic missiles, nuclear cruise missiles, a new generation of bomber planes and weapons capable of penetrating deep underground.

“We are building a new bomber that we don’t need, and then we’re going to outfit it with a new cruise missile we don’t need,” Cirincione said. “It is a redundancy on top of a redundancy.”

Budget cuts: For fiscal 2017, the Obama administration has proposed its smallest nuclear security budget ever. The proposal would slash spending for the National Nuclear Security Administration’s international program by roughly two-thirds, to a level last seen in the mid-1990s.

One reason for the cut is that a portion of budgets over the past two decades went to securing material in the former Soviet Union. But that does not explain the entire reduction; plus, there are new needs.

“The administration is now projecting lower spending year after year for years to come, postponing or canceling a wide range of nuclear security activities that had been included in earlier plans,” said a new report by Harvard University’s Belfer Center.

“Nuclear weapons are up, up, up, and controlling them is down, down, down,” Matthew Bunn, a Harvard professor and one of the Belfer Center co-authors, said in an interview.

Securing nuclear materials: Though the security for nuclear materials has improved “modestly” since the last summit, “the capabilities of some terrorist groups, particularly the Islamic State, have grown dramatically, suggesting that in a net calculation, the risk of nuclear terrorism is higher than it was two years ago,” William H. Tobey, a professor at Harvard’s Belfer Center, said in recent congressional testimony.

Last December’s discovery of a video of the home of a senior official of a Belgian nuclear research center has heightened fears. The video was taken by people linked to the Paris terrorist attacks and to the Islamic State.

Japan’s plutonium delivery to the United States will slip in just in time to meet Japan’s pledge. But if Japan finishes its Rokkasho reprocessing facility, it will produce even more plutonium, adding to its large stockpiles and creating new security risks.

“So we’ve made some modest progress . . . but there are some countries that are going in the other direction,” Carl Robichaud, a program officer at the Carnegie Corp. of New York, said in a recent briefing. The new material could be “as many as tens of weapons’ worth each year that would quickly dwarf the amount that has been blended down and eliminated,” he said.

Ending reprocessing: Reprocessing plants, which can produce tons of dangerous material, have been shut down in Britain, France and Belgium, and one in the United States may never be finished.

However, in addition to Japan’s plant, new reprocessing plants have been completed or are under construction in Pakistan and India. China, which was given a green light in a nuclear cooperation agreement that the Obama administration approved, is considering construction of commercial-scale reprocessing plants. Russia is planning to build a new reprocessing plant, too, the Belfer Center report said.

These costly projects aren’t just bad commercially. They may also herald a new arms race in Northeast Asia, some fear, and heighten the danger of material finding its way into a terrorist bomb.

“The real issue is the U.S. failure to address the threat posed by growing stockpiles of plutonium,” Robert Gallucci, a former special envoy for nonproliferation at the State Department, wrote last year. “The president’s approach to nuclear security may well make matters worse.”

Russia: Russia poses many challenges, including corruption. From 2009 to 2012, the state nuclear company Rosatom fired 276 managers and executives for corruption. One helped run a reprocessing facility. “It makes you nervous,” said Bunn.

With its economy under pressure from low oil prices and international sanctions, Russia says it will cut budgets across the board and fire 10 percent of state employees this year. Rosatom’s budget will not escape, meaning fewer funds to pay for security.

The level of U.S. assistance for securing Russia’s nuclear material that Nunn championed is over. And Russia in December 2014 severed nuclear security cooperation after the United States, as part of sanctions, cut off other nuclear energy cooperation.

Even as terrorist threats grow, conventional ones remain. Bruce Blair, a nuclear security expert at Princeton University, says the United States and Russia still have 1,700 weapons on launch ready alert. Blair has been urging both governments to “relax their postures,” but he said two senior administration officials told him it was not prudent. “It was a bogus analysis,” Blair said.

“Dealing with Russia is the key to dealing with nuclear issues. We have to dance on the dance floor together, otherwise things don’t happen,” said Nunn. “With both countries having the ability to destroy each other in a short time, the continuing posture, in my view, is very, very dangerous over a long period of time. We’ve been fortunate.”

Russia’s violation of the Intermediate-Range Nuclear Forces Treaty and its “refusal to negotiate reductions of non-strategic nuclear weapons, together with the growth of nuclear weapons arsenals in North Korea, Pakistan, and perhaps elsewhere, leave this goal [of nuclear security] more distant today than it was seven years ago, and with no visible path to achieving it,” Tobey said.