KIEV, Ukraine — In 2014, for the first time in seven decades, a state sought to redraw Europe’s map by way of military aggression. Russia’s theft of Ukraine’s Crimean peninsula commanded condemnation and economic sanctions from around the world. But as the news coverage moved on, Moscow was left to design a new assault: a 12-mile bridge between Russia’s mainland and Crimea.

The Ukrainian people will not watch as Russia continues its creeping annexation of our country. Four years ago, in the aftermath of our revolution, Ukraine alone was not able to withstand a Russian military adventure. But today our resolve is strong, and we are prepared to stand up to Russia. This is why I have enacted limited martial law in Ukrainian territory near the Russian border, so that we are able to mobilize and protect our security should Russia dare to intensify its aggression. But we also need the support of the international community in the form of further sanctions against Moscow for its latest assault.

Russia’s attack in the Kerch Strait and the Black Sea on Nov. 25 was not an isolated incident. Since 2014, Russia has regularly violated international rules of navigation and treaties in both those waters and the Sea of Azov. It has stolen our energy supplies and fisheries, harmed Ukrainian livelihoods, and blocked traffic and trade to our ports.