From a New York Times story by Spencer Bokat-Lindell headlined “Putin Is Brandishing the Nuclear Option. How Serious Is the Threat?”

Over the weekend, as his military laid siege to Ukraine for the fourth day, President Vladimir Putin ordered Russia’s nuclear forces into a higher state of alert, the first time the Kremlin has done so since the Russian Federation was established in 1991.

“This is unprecedented in the post-Cold War era,” Daryl Kimball, the executive director of the Arms Control Association, a Washington nonprofit, told NBC. “There has been no instance in which a U.S. or a Russian leader has raised the alert level of their nuclear forces in a middle of a crisis in order to try to coerce the other side’s behavior.”