None of that matters to President Donald Trump, who announced Friday night that he would meet the globally shunned leader this Friday in Alaska. What does matter to Trump is that he may be able to stop the bloodshed in Ukraine, the worst European conflict since World War II, fulfilling one of his biggest campaign promises.

Unlike Putin’s military seizure of about a fifth of Ukraine, Russia’s 19th-century sale of Alaska to the US under Emperor Alexander II was a peaceful transaction. Still, it serves as a reminder that national borders are not set in stone, and land can be a currency for statecraft.

For President Vladimir V. Putin of Russia, it is an opportunity not just to end the Ukraine war on his terms, but to split apart the Western security alliance.