But just where the dividing line is remains unclear, because Russian President Vladimir Putin may yet attempt to capture the strategic port of Mariupol on the Sea of Azov, thereby enabling the Kremlin to create a land bridge between Russia and the Crimea peninsula. Moreover, capturing Mariupol would keep open the option of conquering southern Ukraine, including Odessa, and extending Russian control all the way to Transnistria, Russia's illegal enclave in Moldova.