With tens of thousands of Russian troops positioned near Ukraine, the Kremlin has kept US and its allies guessing about its next moves in the worst security crisis to emerge between Moscow and the West since the Cold War. Amid fears of an imminent attack on Ukraine, Russia has further upped the ante by announcing more military drills in the region. It also has refused to rule out the possibility of military deployments to the Caribbean, and President Vladimir Putin has reached out to leaders opposed to the West.

The military muscle-flexing reflects a bold attempt by the Kremlin to halt decades of NATO expansion after the end of the Cold War. In talks with the United States, Russia demands legally binding guarantees that the alliance will not embrace Ukraine and other former Soviet nations, or place weapons there. It also wants NATO to pull back its forces from countries in Central and Eastern Europe that joined the alliance since the 1990s.