Its preventive war in Ukraine jolted Europe, but Russia’s abysmal performance revealed its weakness—and it’s weakened further over the last year. Russian aggression also increased European unity and reinvigorated military spending debates inside many allied capitals. And the balance of power already significantly favored NATO-Europe.

While it remains the biggest conventional threat to European security, the Russian threat is diminishing. With higher priorities elsewhere, the U.S. faces a choice about the burdens of securing the continent: it can keep them or shift them to our wealthy allies.