When the Navy destroyer USS Donald Cook sailed into the Baltic Sea in April 2016, it had been more than two years since Russia seized Crimea from Ukraine.
Tensions between Russia and its NATO and European neighbors were still high, and the intervening period had seen a number of uncomfortable and even unsafe encounters between their forces, for which NATO often criticized Russia.
Adm. James Foggo, then a vice admiral in charge of the Navy's Sixth Fleet, had those in mind as the Cook sailed into the Baltic.
U.S. Navy photo by Mass Communication Specialist Seaman Edward Guttierrez
The Cold War-era Su-24 “Fencer” strike jet was designed to penetrate enemy air defenses at low levels. And a pair of Russian Su-24s appeared to be testing their ability to do just that when they flew a series of simulated attacks runs on the USS Donald Cook soon after it departed from the Polish port of Gdynia.