Wooing Allies, Publicizing Putin’s Plans: Inside Biden’s Race to Prevent War

President Biden made three critical decisions about how to handle Russia’s provocations, aiming to prevent armed conflict in Ukraine.

WASHINGTON — In a series of top-secret meetings last October, President Biden’s national security team presented grim intelligence that would soon trigger a fierce effort to prevent what could become the largest armed conflict in Europe since World War II.

Vladimir V. Putin, the Russian president, was preparing to invade Ukraine, top intelligence and military officials told Mr. Biden. Gathering each morning in the Oval Office for the global threat assessment known as the President’s Daily Brief, they described satellite images of Russian forces methodically advancing toward Ukraine’s border.

Not only did the United States have images of troops moving into position, it also had the Russian military’s plans for a campaign against Ukraine — elements of which had already begun. At one of the morning meetings, Mr. Biden dispatched William J. Burns, the C.I.A. director, to Moscow with a message for Mr. Putin: