Two of Russia’s chief preoccupations—its vulnerability on land and its lack of access to warm-water ports—came together in Ukraine in 2014. As long as a pro-Russian government held sway in the Ukrainian capital of Kiev, Russia could be confident that its buffer zone would remain intact and guard the European Plain. Even a neutral Ukraine, which would promise not to join the European Union or NATO and would uphold the lease Russia had on the warm-water port at Sevastopol in Crimea, would be acceptable. But when protests in Ukraine brought down the pro-Russia government of Viktor Yanukovych and a new, more pro-Western government came to power, Putin had a choice. He could have respected the territorial integrity of Ukraine, or he could have done what Russian leaders have done for centuries with the bad geographic cards they were dealt. He chose his own kind of attack as defense, annexing Crimea to ensure Russia’s access to its only proper warm-water port, and moving to prevent NATO from creeping even closer to Russia’s border.

The same geographic preoccupations are visible now in Russia’s intervention in Syria on behalf of Putin’s ally, Bashar al-Assad. The Russians have a naval base in the port city of Tartus on Syria’s Mediterranean coast. If Assad falls, Syria’s new rulers may kick them out. Putin clearly believes the risk of confronting NATO members in another geographic sphere is worth it.

Russia has not finished with Ukraine yet, nor Syria. From the Grand Principality of Moscow, through Peter the Great, Stalin, and now Putin, each Russian leader has been confronted by the same problems. It doesn’t matter if the ideology of those in control is czarist, communist, or crony capitalist—the ports still freeze, and the European Plain is still flat.