On February 5, the Strategic Arms Reduction Treaty (New START, or START-3), which limited the number of deployed warheads and delivery systems in Russia and the U.S., will expire. Once the treaty lapses, not only will these two countries be able to begin expanding their nuclear arsenals based on worst-case assumptions about each other’s actions, but other nations will no longer feel constrained either, reports The Moscow Times.
Without New START, which entered into force in 2011 and was extended for five years in 2021, Moscow and Washington will, for the first time since the Cold War, be without a mechanism to regulate their nuclear stockpiles. “The world will certainly not become safer,” says Pavel Podvig, senior researcher at the UN Institute for Disarmament Research (Bloomberg). The main loss, he notes, is transparency, because under the treaty the parties could conduct inspections of each other’s nuclear facilities and were required to exchange information. Vladimir Putin, in fact, suspended Russia’s participation in the treaty in 2023, but now the official absence of verification and restraint systems “will only increase political risks,” Podvig believes.
The removal of these limits will likely lead to nuclear buildup not only by Russia and the U.S., but also encourage other countries—from the U.K. and France to North Korea and Pakistan—to expand their arsenals, according to Mackenzie Knight-Boyle, senior fellow at the Nuclear Information Project of the Federation of American Scientists.
The immediate danger, she says, is that in the absence of legal limits and verification measures, Russia and the U.S. will return to “worst-case” planning and begin replenishing already-deployed forces with hundreds of warheads out of concern that the other side is doing the same. This would allow them to “rapidly increase the number of deployed nuclear warheads in a short period of time,” Knight-Boyle notes.
The situation is extremely uncertain, agrees Daryl Kimball, executive director of the Arms Control Association (Politico):
“Unless Trump and Putin reach some sort of understanding soon, it’s not unlikely that Russia and the U.S. will start to upload more warheads on their missiles.”
The total number of warheads among the nine nuclear-armed countries was 12,241 as of January 2025, according to the Stockholm International Peace Research Institute (SIPRI); of these, 9,614 are potentially deployable.
Donald Trump has repeatedly stated that he would like a new nuclear arms treaty to include China. At the start of the decade, China had around 200 warheads, and by its end, according to Pentagon estimates, this could rise to 1,000—compared to 3,700 in the U.S. and 4,309 in Russia (SIPRI data; New START limited deployed warheads to 1,550). Moscow, for its part, insisted that the U.K. and France (with 225 and 290 warheads, respectively) be included.
China remains far from U.S. nuclear capability, said Foreign Ministry spokesperson Lin Jian at a briefing on February 3:
“At this stage, it is unfair and unreasonable to demand that China join nuclear disarmament negotiations.”
The U.K. and France also have no intention of limiting their forces, especially since they may need to extend their nuclear umbrella to other European countries at a time when U.S. readiness to do so has become uncertain.
“Russia will maintain a responsible and careful approach to strategic stability in the field of nuclear weapons and will primarily be guided by national interests,” said Dmitry Peskov on Thursday.
Trump will decide on further steps regarding nuclear arms control and announce them when he deems appropriate, a White House official told Politico. The Pentagon has held a series of closed meetings in preparation for the post-New START scenario, but it is unclear exactly what was discussed, according to three people familiar with the meetings.
Several Democrats in Congress have recently introduced a bill requiring the administration to pursue reductions in nuclear weapons through negotiations. One of the bill’s sponsors, California Congressman John Garamendi, said:
“If we allow the New START treaty to expire without replacement or extension, we will enter a new, terrifying world that has not been seen in decades—a world without limits on the arsenals of the two largest nuclear powers.”
