It's not by chance that the countries' 4 1/2-year conflict has taken on a naval dimension. Moscow is further imposing on Kiev its annexation of Crimea.
The countries are trading blame over a maritime dispute in which Russia fired on Ukrainian vessels, injuring some sailors. The incident has sparked Ukrainian protests and an international backlash.
The Russian leader jumped behind the wheel of an orange dump truck, leading the charge across the 12-mile bridge connecting the two regions for the first time in history.