WASHINGTON — President Trump is sending a high-level delegation to meet with Russian counterparts in Geneva this week to pursue an arms control treaty that for the first time would cap the nuclear arsenals of not just the two largest powers, but China as well.
Mr. Trump broached the idea with President Vladimir V. Putin of Russia during their meeting in Osaka, Japan, last month and has also signaled his ambition for such a three-way accord to President Xi Jinping of China, administration officials said on Monday. Russia has expressed interest; China has not.
The meeting comes at a fraught moment in the history of arms control between Washington and Moscow. Mr. Trump’s decision to withdraw from the Intermediate-Range Nuclear Forces Treaty of 1987, or I.N.F., on the grounds of Russian violations takes effect next month over Mr. Putin’s objections.
Mr. Trump’s team has also signaled that it is not interested in renewing the New Start treaty of 2010 that expires in 19 months despite Russia’s entreaties to keep it.
Instead, Mr. Trump’s administration argues that two-way Russian-American arms agreements dating to the Cold War are antiquated in a world where China is a rising power, although it remains unclear how committed he really is to any new accord given his administration’s skepticism of arms control.
Beijing has long argued that it maintains only a relatively small arsenal of weapons for deterrence. But the Defense Intelligence Agency estimated in May that China is “likely to at least double the size of its nuclear stockpile” in the next decade.
Even so, the United States and Russia together still possess more than 90 percent of the nuclear weapons in the world today. According to the Arms Control Association, the United States has 6,185 warheads, while Russia has roughly 6,490 and China has about 290.
Those totals include both strategic warheads limited by the New Start treaty as well as shorter-range weapons that are not covered and other warheads that are no longer in military service and awaiting dismantlement.
The delegation to Geneva will be led by John J. Sullivan, the deputy secretary of state, and will include Tim Morrison, who is taking over as Mr. Trump’s top Russia adviser on the National Security Council staff, plus representatives of the Pentagon, the National Security Agency and other agencies. The Russian delegation will be led by Sergei Ryabkov, the deputy foreign minister.
China will not participate in this meeting, and Mr. Trump’s aides said they do not know yet whether they will try to convene a three-way negotiation or first come up with the framework of an agreement with Moscow and then approach Beijing.
Chinese officials have categorically rejected the idea regardless of how it is negotiated, citing, among other things, Mr. Trump’s decision to pull out of the I.N.F. treaty as evidence that the United States cannot be trusted.
“As to the trilateral negotiations on arms control, China’s position is clear-cut,” Lu Kang, the spokesman for China’s Foreign Ministry, said in May. “The premise and basis for trilateral arms control negotiations do not exist at all, and China will never participate in them.”
Mr. Putin told Mr. Trump in Osaka that he was open to such a negotiation, according to American officials, but was more interested in renewing the New Start treaty, which expires in February 2021. John R. Bolton, Mr. Trump’s national security adviser, said last month that it “would be malpractice” to renew the treaty unless it were rewritten to cover weapons not currently limited.