MOSCOW — Secretary of State John Kerry had just made an offhand remark about how President Bashar al-Assad of Syria could avoid a military strike — and now Sergey V. Lavrov, Russia’s hard-charging foreign minister, was on the phone.
Mr. Lavrov was not about to let the moment pass. What aides to Mr. Kerry were already t
rying to roll back, Mr. Lavrov seized on, telling Mr. Kerry he would immediately go public with a Russian-led proposal to dismantle the Syrian chemical weapons arsenal. That prompted a sharp response from Mr. Kerry who warned in the 14-minute call, “We are not going to play games.”
By the time Mr. Kerry’s plane landed back in Washington, the ground had shifted and on Saturday, not a week later, Mr. Kerry and Mr. Lavrov completed the plan sitting by the pool at a Geneva hotel.
It is a pact that American arms control experts have scrambled to shape and that the White House believes may be the best way to the uphold prohibitions against the use of poison gas without resorting to military force. But it is also one that the Kremlin clearly thinks serves the interests of Russia and the Syrian government.
In many ways, Mr. Lavrov’s work over the next six days represented the apex of a career largely spent trying to body-block what the Kremlin has long viewed as dangerous American unilateralism. It is a job he has done so effectively that it has earned him the nickname “Minister Nyet,” and senior American officials, including Hillary Rodham Clinton and Condoleezza Rice, have said they often found it infuriating to deal with him.
As the diplomatic technician for his boss, President Vladimir V. Putin, Mr. Lavrov maneuvered to hem in the United States, averting a unilateral military strike and reasserting Russia’s role — all while Russia was continuing to provide weapons to Mr. Assad and diplomatic cover for his effort to suppress an uprising.
More broadly, though, Mr. Lavrov has sought to force the United States into a conversation that the Kremlin hopes will set a precedent, establishing Russia’s role in world affairs based not on the dated cold war paradigm but rather on its own outlook, which favors state sovereignty and status quo stability over the spread of Western-style democracy.
In doing so, Mr. Lavrov relied on his long experience, not just on nearly 10 years as foreign minister. He served more than a decade as Russia’s ambassador to the United Nations, where he developed an intricate knowledge of the workings of the Security Council, as well as deep experience in international disarmament efforts, including in Iraq.
“For now, he’s one of the most skilled diplomats in the world,” said Fyodor Lukyanov, editor in chief of the policy journal Russia in Global Affairs. “The time of real diplomacy has come back.”
For Mr. Lavrov it is a series of events he has long prepared for. He graduated from the Moscow State Institute of International Relations in 1972 and moved to New York in 1981 to work at the United Nations after brief stints in Sri Lanka, and in Moscow.
At the United Nations, he was known for his elaborate, seemingly absent-minded doodling during lengthy meetings but also for a command of the issues.
“He was a great doodler, but his mind was always spinning away,” said Charles A. Duelfer, who was deputy head of the United Nations’ weapons inspectors program in Iraq in the 1990s and frequently met with Mr. Lavrov at the United Nations headquarters in New York.
Mr. Duelfer said that Mr. Lavrov’s long experience with United Nations inspectors working to remove unconventional arms from Iraq helped him to quickly assess the situation in Syria and to work out a detailed plan with Mr. Kerry. “He knows this stuff because he lived through it in Iraq,” Mr. Duelfer said. “He’s knows what’s possible when you have independent inspectors.”
A more cynical view, analysts and Western diplomats said, is that Mr. Lavrov was after a political objective, not one of disarmament, using diplomatic jujitsu to buy time for the Assad regime.