If, at the outset in 2022, many saw Russia’s war against Ukraine as a regional conflict that might be contained, its nature as a global geopolitical turning point has become ever clearer. The invasion that Moscow launched four years ago next week has forced Europe to rearm and think about future wars on the continent. The Eurasian autocracies have aligned economically, technologically, and strategically in unprecedented ways—bringing Iranian weapons and North Korean soldiers deep into the European battlespace. The economics of energy are shifting as Europe cuts its links to Russia and the dangers of overreliance on a hostile power...