MUNICH — Chances are slipping for the timely extension of a landmark nuclear-weapons treaty that has successfully checked the impulses of the United States and Russia to build ever-growing atomic arsenals.

That is the sobering message from last weekend’s Munich Security Conference, where the former Cold War enemies continued accusing each other of fouling the Intermediate-Range Nuclear Forces Treaty. The poisoned discourse puts into question whether that pact’s bigger sibling, the New Strategic Arms Reduction Treaty, will continue past its February 2021 expiration date, according to analysts.

“The United States is mistrustful of Russia and treaty compliance after the INF experience,” Kori Schake, a deputy director-general of the London-based International Institute for Strategic Studies, told Defense News. “And rightfully so.”

The Trump administration walked away from the missile treaty in early February after years of Washington's complaints that one of Moscow's cruise missile types was secretly deployed or tested in violation of the pact. The next day, Russia announced its intention to also exit the treaty, with top officials saying that new weaponry of the once-prohibited range class would swiftly be developed.

While New START remains in effect for another two years, the clock is ticking, warns François Heisbourg, senior adviser for Europe at the IISS think tank. Given the Trump administration’s “low level of energy” toward extending the accord, Heisbourg warned there is a real danger of its eventual demise. Moscow is equally to blame, he added. “Russia seems on a path to want INF and New START gone.”

While the INF Treaty prohibits the deployment of land-based missiles with a range between 300 miles and 3,000 miles in Europe, the 2010 New START pact places limits on the types of nuclear weapons with global reach. A verification regime ensures both countries adhere to the ceilings of 700 deployed strategic missiles and bombers, as well as 1,550 deployed nuclear warheads.

Speaking at Munich, Russian Deputy Foreign Minister Sergei Ryabkov brought up a technical disagreement that has been dogging New START since last year. The Americans, he said, have converted 56 Trident II submarine launchers and 41 B-52H heavy bombers for non-nuclear use, taking them off the books of the inspection regime. While such conversions are allowed, Ryabkov contends Moscow was left unconvinced that the modifications are irreversible.

"We went several extra miles with the U.S. counterparts in order to present them concrete and specific technical ideas how it can be done, how this problem might be fixed,” Ryabkov said. In his telling, the Americans never responded.

“Thus I believe there is a growing risk of this U.S. administration just purposely continu[ing] talk on the issue as if there is enough time, nothing to worry about, but then the treaty just fades out as of Feb. 5, 2021,” Ryabkov said. “That would be another extraordinary shock for the arms control system.”

According to Heisbourg, a scenario where both nuclear arms-reduction treaties have expired would be highly destabilizing.

“If START also goes, there is no longer a way to know what weapons are nuclear and which are not,” he said. “That means escalation in all planning, toward a nuclear exchange.”

The official Russian position on the strategic treaty is that Moscow wants to talk about a five-year extension, Ryabkov told an audience of world leaders in Munich.

Those rosy proclamations should be taken with a grain of salt, however, said Evelyn Farkas, a former U.S. deputy assistant secretary of defense for Russia, Ukraine and Eurasia.

“The Russians are always ready to talk,” she told Defense News at the sidelines of the conference. “It’s not about talking, it’s about what they are ready to do.”

Farkas said the Trump administration similarly appears to be dragging its feet. “I suspect that New START talks aren’t high up on their list right now. And I don’t expect them to start anytime soon.”