Sunday’s escalation came when Ukraine tried to move three navy vessels from Odessa on the Black Sea to Mariupol. The Russian authorities proved unwilling to let warships, even small ones, pass. Though Ukraine warned Russia that the ships were coming, the Russian coastguard rammed one of the vessels and seized all three, wounding six sailors, according to the Ukrainian navy. Russia also blocked the passage under the Kerch Strait bridge with a container ship and sent warplanes.

Ukraine’s reaction was forceful. It called a United Nations Security Council meeting for Monday, demanding more sanctions against Russia. Foreign Minister Pavlo Klimkin warned that Russia could be planning “further acts of aggression.” And Ukraine’s Security and National Defense Council recommended martial law for 60 days – something Ukraine never did during the Crimea annexation and several big battles in the country’s east. Poroshenko backed the decision, and the Ukrainian parliament will probably a

pprove it.

Formally, there’s a reason to introduce martial law now that didn’t exist during the bloodiest fighting. Russia has denied involvement in those battles in Ukraine’s east; as it did during the Crimea annexation before it admitted sending troops. Now, however, Russian forces have openly attacked Ukrainian ships in violation of a treaty. It’s no stretch to interpret this as an act of war.

Russia, though, has been quick to point out that the escalation benefits Poroshenko domestically. Russian Deputy Foreign Minister Grigory Karasin called the Ukrainian warships’ voyage a “provocation.” “Apparently, against this background it’s easier for Poroshenko to unfold his election campaign,” Karasin said.

The presidential election is scheduled for March 31. It can’t be held while the country’s under martial law, but if it’s introduced for 60 days only, the vote can take place as planned. Yuri Birukov, a Poroshenko aide, wrote on Facebook on Sunday that the administration doesn’t intend to put off the election.