Russia has been waging low-intensity war against Ukraine for over four years. During that time, Moscow has endeavored to disguise its role in the struggle, using cutouts — "little green men" who had no obvious ties to Russia but enjoyed its support — and tactics — cyberattacks and economic pressure — that fall short of open conflict. Russia shed the fig leaf last weekend when it seized three Ukrainian Navy ships in the Kerch Strait that links the Azov and Black seas. The move is a challenge not just to the government of Ukrainian President Petro Poroshenko, but to the West: It is no coincidence that the incident occurred days before Russian President Vladimir Putin attends the Group of 20 summit in Argentina. It must be met with steely determination.
Baldly stated, Russia seeks a sphere of influence in Eastern and Central Europe. It believes that countries on its periphery, and especially those that were part of the Soviet imperium, should be responsive to Russian interests and respect its concerns.
Ukraine, which seeks closer ties to the European Union and NATO, is a direct challenge to that order, and must be brought to heel. To do so, Russia annexed the Crimean Peninsula from Ukraine in 2014 and has supported separatists fighting in the Donbass region of eastern Ukraine. It is estimated that over 10,000 lives have been lost in the fighting, and the war undermines the legitimacy of the Poroshenko government: A leadership that cannot protect its own territory does not deserve to govern.