Prevent the outbreak of another global security threat. Extend New START.

As the United States and other nations appropriately focus on the steps necessary to deal with the deadly effects of the coronavirus pandemic and its economic fallout, the international community cannot afford to lose sight of the other global challenges that threaten all of us: the worsening planetary climate emergency and the ongoing threat of catastrophic nuclear war.

We’re not only at a pivotal point in the struggle against the fast-moving coronavirus; we are also at a tipping point in the long-running effort to reduce the threat of nuclear war and eliminate nuclear weapons. Tensions between the world’s nuclear-armed states are rising; the risk of nuclear use is growing; billions of dollars are being spent to replace and upgrade nuclear weapons; agreements that have kept nuclear competition in check are in serious jeopardy.

At a UN Security Council session on nuclear weapons issues convened in February, the high representative for disarmament affairs, Izumi Nakamitsu, warned that “relationships between states, especially nuclear-weapon states, are fractured. The specter of unconstrained nuclear competition looms over us for the first time since the 1970s. Regional conflicts with a nuclear dimension are worsening, and proliferation challenges are not receding.”

One of the most important ways to move the world further away from the nuclear precipice would be for President Trump to take up Russia’s standing offer to extend the only remaining treaty limiting the world’s two largest nuclear arsenals—the New Strategic Arms Reduction Treaty (New START)— for five years and ultimately build on New START for a more comprehensive arms control regime in the future.

Nothing would be so out of step with the national and international mood—and the United States’ own national interest—than opening the door to an expensive nuclear arms race in the midst of a devastating pandemic.

New START, which was signed 10 years ago, verifiably caps each nation’s strategic nuclear arsenals at no more than 1,550 deployed warheads and 700 missile and bomber delivery platforms. The treaty has worked well for both sides. The latest data exchange mandated by the treaty shows Russia with 1,326 deployed warheads on 485 deployed delivery systems, while the United States currently deploys 1,373 warheads on 655 delivery systems. That is lowest Russian warhead total since the treaty entered into force in 2011.

Time is running short, however. New START will expire on February 5, 2021 unless US and Russian leaders agree to extend it. They can do so by mutual agreement for a period of up to five years. Before they do, the two sides may choose to meet to resolve potential differences regarding the legal modalities of treaty extension, which new strategic nuclear systems would continue to be covered by the treaty, and how New START’s on-site inspections and counting rules might be applied.

So far, the Trump administration has dithered on a decision and refused to engage with Russia in discussions on extension, claiming there is ample time to do so. Russian officials beg to differ.

The US delay is a very worrying sign. Trump has shown a willingness to walk away from other effective nuclear risk-reduction agreements, including the 2015 Iran nuclear deal. He and his team prematurely abandoned the Intermediate-Range Nuclear Forces Treaty after a perfunctory effort to address a compliance dispute. Reports suggest the administration is determined to unilaterally withdraw from the 1992 Open Skies Treaty.

Yet, at times, President Trump says he wants to want to reduce the nuclear danger and avoid a costly arms race. Last year he said: “Between Russia and China and us, we’re all making hundreds of billions of dollars-worth of weapons, including nuclear, which is ridiculous.”

Yes, it is ridiculous. In February, the White House proposed to Congress a 19 percent increase in taxpayer spending—from the $37.3 billion for fiscal year 2020 to $44 billion for fiscal 2021—to replace and upgrade the US nuclear arsenal in the coming year. Russia is also pursuing costly upgrades to its nuclear force and is determined to match the United States weapon-for-weapon.

If President Trump allows New START to lapse with nothing to replace it, there would be no limits on the world’s two largest nuclear arsenals for the first time since Washington and Moscow concluded the Strategic Arms Limitation Treaty in 1972.

Without New START, either side could rapidly upload hundreds of additional nuclear warheads to its missiles, bombers, and submarines. Both sides would lose the robust verification and monitoring provisions that are so highly valued by their military leaders and US allies. The already fraught US-Russian relationship would become even more difficult as the risk of a nuclear competition grows.

No one would win a costly and destabilizing nuclear arms race, which is why verifiable nuclear arms control has been a part of US strategy for more than 50 years.

Extension of New START would open the way for the US and Russian presidents to launch follow-on talks aimed at achieving further cuts in all types of nuclear weapons—both shorter-range and longer-range. Preserving New START would also create a much more favorable environment for pursuit of President Trump’s goal of “involving China,” which has a deadly but significantly smaller nuclear arsenal, estimated at around 300 weapons.

Involving other countries, particularly China, in the nuclear disarmament process is a worthy objective. The United States, Russia, China, Britain and France, all nuclear-armed states parties to the Treaty on the Nonproliferation of Nuclear Weapons, are obligated to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament ….”

As Henry Kissinger, Bill Perry, Sam Nunn, and George Shultz wrote in 2007, the United States needs to engage in “intensive work with leaders of the countries in possession of nuclear weapons to turn the goal of a world without nuclear weapons into a joint enterprise.”

Achieving concrete results in these areas will, however, be difficult and will take time. And direct, face-to-face diplomacy is not practical so long as the coronavirus remains a threat.

Last month, US and Russian officials agreed to suspend the on-site inspections required under New START and they cancelled a regular spring meeting to discuss implementation of the treaty because of the risk posed by the pandemic. If US and Russian diplomats and technicians cannot meet to implement an existing treaty, US, Russian, and Chinese officials can’t possibly engage in the direct talks that would be required to hammer out a new agreement.

In any case, the Trump administration is not ready for a new “trilateral” negotiation and won’t be for some time. It has been a year since the White House said it was delaying its decision on New START extension in order to explore a more ambitious nuclear deal with Russia and with China. Yet the administration has not concluded its internal deliberations on what such a deal might look like, nor has the White House formally named a negotiator for such an effort.

One other significant hurdle: Leaders in Beijing insist they will not engage in trilateral arms control negotiations so long as there is such a large disparity in the size of the Chinese and the US/Russian nuclear arsenals.

Taking all this into account, it is abundantly clear that even if President Xi Jinping were to agree to negotiate on nuclear arms control matters with Trump and Putin, it would be all but impossible to conclude a new, trilateral arms control nuclear deal before New START expires—which makes the extension of New START the only practical option.

Nevertheless, Trump remains intoxicated with the idea of holding out for what his advisors call “a new era of arms control.” On Feb. 28, President Trump announced he would be willing to meet other leaders of the Permanent Five (P5) members of the UN Security Council on international security matters, including arms control, as proposed by President Putin. A wide-ranging, one-day heads of state summit, however, is not a negotiation.

At best, such a meeting (if it happens) could be a catalyst for a decision to extend New START, an agreement to pursue follow-on talks between Washington and Moscow on further nuclear cuts, and the start of a discussion with the leaders of the other nuclear states, including China, on how they could contribute, including by agreeing to a freeze on the size of their arsenals. To reduce nuclear tensions and improve the prospects for success, President Trump and the other P5 leaders could also use the meeting to issue a joint declaration reaffirming the 1985 Reagan-Gorbachev statement that “a nuclear war cannot be won and must never be fought.”

These words can make a difference. Such a statement would underscore that all five countries understand they have a responsibility to prevent nuclear catastrophe and improve the environment for the pursuit global nuclear disarmament.

The Trump administration has been rightly criticized for ignoring multiple warnings about pandemics and for failing to provide our nation’s public health system with the resources and equipment necessary to deal with the effects of the virus on the American people. There is an obvious parallel to the threat of nuclear weapons: Multiple warning signs strongly suggest that unless the leaders of the world’s nuclear-armed states exercise prudent, mutual restraint and engage in pragmatic diplomacy, the catastrophic possibility of nuclear war will increase.

A prompt decision by President Trump to renew New START would not only help head off the costly nuclear arms race the president says he doesn’t want—it would help protect the nation and the world from a threat for which the only cure is prevention.