Updated May 21, 2020 9:31 pm ET
The Trump administration says that it plans to propose more intrusive verification measures than under New START. This includes a demand for greater sharing of missile-test telemetry and measures that allow faster on-site inspections.
The British and French nuclear forces wouldn’t be part of the accord under the U.S. plan, though Russian officials have sometimes argued that they should.
Negotiating a major arms-control treaty is a yearslong process, raising the question of what constraints will be kept in place once the negotiations are under way.
The New START treaty can be extended for as many as five years by mutual consent. But Trump officials have hinted the U.S. may not do so unless the new three-way negotiations have begun and are making headway.
The collapse of the New START constraints, and the verification provisions it includes, would mark a further unraveling of the arms-control regime. Last year, the U.S. withdrew from the Intermediate-range Nuclear Forces Treaty, which it alleged Moscow was violating.
Of all the looming obstacles toward a new accord, the principal one is persuading China to join.
China has about 320 warheads, according to the Federation of American Scientists. That is a fraction of the 1,750 nuclear weapons the U.S. has deployed on its long-range and shorter-range systems, among the 3,800 warheads in the U.S. stockpile, according to the group’s estimate.
The U.S. Defense Intelligence Agency has said, however, that the Chinese arsenal is expected to at least double over the next decade.
Frank Klotz—a retired three-star general and the former head of the National Nuclear Security Administration, which oversees the development of the U.S. nuclear arsenal—said that the idea of drawing China into a new three-way accord was fraught with difficulties.
Establishing equal limits on Chinese, U.S. and Russian forces wouldn’t be an option in seeking a new agreement because Washington doesn’t want to allow China to match the current American level. Nor does the Pentagon want to cut its force to China’s level.
“Why would the Chinese agree to be locked into a three-way agreement at significantly lower numbers than the U.S.?” Mr. Klotz said. “Why would Russia or the U.S. agree to allow China to have numbers equal to Russia and the U.S.”
—Gordon Lubold and James Marson contributed to this article.
Write to Michael R. Gordon at firstname.lastname@example.org