US Blackhawks and Apaches train with Russian attack helicopters nearby

MIHAIL KOGALNICEANU AIR BASE, Romania — As Russian attack helicopters hovered menacingly near NATO’s eastern border in late spring, it became clearer to the American pilots at the Romanian base known as “MK” why they were stationed at this far-flung location on the Black Sea.

The Russian troop buildup in Crimea and on the eastern border of Ukraine in late March reached 100,000 troops. Tanks, rocket systems, fighter jets, and attack helicopters were also positioned. Vladimir Putin’s first test of President Joe Biden led to a phone call promise of withdrawal, followed by a summit in Geneva last week that included compliments of the American leader from the former KGB officer.