For the first time in a millennium, Europe no longer plays a critical role in promoting Western civilization nor in world history at large.

Ostensibly it should. Some 750 million people live on the European subcontinent.

Europe still remains the most popular tourist spot on earth. Its hallowed architecture, art, infrastructure and natural beauty still remind millions of visitors of the world’s once most dynamic and grandiose civilization.

Even now, European nations, in and out of the Europe Union, still produce a combined gross domestic product of $24 trillion, second only to the United States.

Europe’s exports are among the world’s most coveted cars, sophisticated technology and valued industrial goods.

Yet since World War II, Europe has played an increasingly reduced role in world affairs, despite its membership in the NATO alliance and the growth of the European Union.

Why?

The 20th-century traumas of World War I and II — in which some 70 million Europeans were killed — saw Europe commit near collective suicide. The ensuing Cold War hinged on protecting a relatively unarmed Europe from an aggressive nuclear Soviet empire on Europe’s borders.

But as World War II and the Cold War faded into memory, Europe did not snap back and assume its centuries-old role as a world leader and beacon of Western Civilization.

Instead, a weary Europe outsourced its security to the United States. It redefined itself as a postmodern, pacifist, socialist utopian project — most recently predicated on redistributionist entitlements, open borders and radical green policies that have all inevitably ensured European decline.

Europeans grew louder and whinier the less relevant they became.

Although Europe has large sources of untapped hydroelectrical, nuclear, coal and natural gas power, its green religion has all but shut down new nuclear and fossil fuel generation and closed existing plants. The result is that the cost of European energy is prohibitive for both the public and industry.

Recent economic growth was essentially zero throughout the Eurozone. The European cradle-to-grave social net, and its hyper government regulations and restrictions on economic activity increasingly are unsustainable.

Few European nations spend even a mere two-percent of their GDP on defense. And the result is that both Europe at large and its NATO members cannot defend their continent without the assistance of the United States.

Nor can Europe project power beyond its shores to preempt dangerous threats on its own horizon or to its allies.

Europe is also shrinking and aging. Its collective fertility rate of 1.5 is far below the rate of replacement. Most young people in Europe — the ancient home of Christendom — express neither belief in God nor any faith in organized religions.

In many European countries, foreign-born emigrants comprise 20 percent of the population. Most of them have arrived poor, without education, in mass, illegally, with little desire to fully integrate, from inimical countries, and holding political and religious views hostile to Europe.

The other half of the West is in little better condition.

The United States is reeling under $33 trillion in national debt.

After embracing various bankrupt academic critical legal “theories,” major American cities are unsafe, unhealthy and unsightly. The American southern border is wide open. Eight million illegal aliens have poured in just since January 2021, many of them hostile to the United States.

America is increasingly politically, racially and tribally divided. It has mysteriously determined not to fully utilize its vast natural resources, especially gas, oil and rare earth metals.

In this vacuum, the enemies of the West see only opportunity.

Russia invaded European Ukraine. Its ongoing aggression still terrifies frontline NATO nations.

China threatens periodically to storm Taiwan, as it bullies its neighbors, buzzes U.S. ships and planes and manipulates currency, markets and trade.

Iran has armed to the teeth anti-Western terrorist organizations like Hezbollah and Hamas.

Iran’s “Shiite Crescent” from Tehran to Damascus to Beirut to Palestine threatens both pro-Western Arab regimes and Israel.

Iran brags that its surrogates can destroy Israel and will soon be nuclear with a global reach to both the United States and Europe.

Hamas attacked Israel on October 7, presumably on the assumption that current generations of Westerners in Israel, the U.S. and Europe would not react too strongly to its precivilizational barbarity if it entailed a subsequent messy war.

In sum, the world is safe only when a strong America, alongside its European partner, secure their borders, protect the world’s sea and air spaces, support constitutional and pro-Western nations and deter thuggish belligerents.

Perhaps as war clouds gather and enemies multiply, Europe will rediscover its heritage and reawaken to its historical role.

Increasingly, a lonely U.S. — and the world at large — need the return of a sane and powerful European co-partner, one that emerges from its self-induced slumber, and resumes its ancient role in preserving civilization from its multiplying enemies.

Victor Davis Hanson is a distinguished fellow of the Center for American Greatness. He is a classicist and historian at the Hoover Institution, Stanford University, and the author of “The Second World Wars: How the First Global Conflict Was Fought and Won,” from Basic Books. You can reach him by e-mailing authorvdh@gmail.com.