Walk the beautiful streets in Munich, Strasbourg and Vienna, and you can see why Europeans thought in the last decades that they had reached the end of history. There is not a soldier to be seen. Sidewalk cafes are jammed midweek with two-hour lunch-goers. Fashion, vacations and sex dominate the ads and billboards.

Bikers, electric commuter trains and tiny fuel-efficient cars zoom by in a green contrast to our gas-guzzling Tahoes and Yukons.

So naturally, there is a general sense of satisfied accomplishment among European social democrats. They believe that finally a quiet sameness across their continent has replaced two millennia of constant European warring and revolution. Now, everybody seems to get an apartment, small car, state job, good pension and peace — and in exchange, all voice comfortable center-left consensus politics.

But beneath the genteel European Union veneer, few remembered that human nature remains constant and gives not even nice Europeans a pass from its harsh laws.

So suddenly the Greek financial meltdown, and the staggering debts that must be repaid, have alternately enraged and terrified northern European creditors. Even the most vocal Europhiles are quietly rethinking the entire premise of a European Union that offers lavish benefits but no sound method of paying for them.

After all, it is one thing to redistribute income by taking from richer Germans and Austrians to give to poorer Germans and Austrians. But it is something else for all Germans and Austrians to extend their socialist charity to siesta-taking Greeks, Italians and Spaniards. For all the lofty rhetoric of the collective European Union, age-old culture, language and nationalism still trump the ideal of continental unity.

But bickering over a trillion dollars in bad southern European debt is not the EU's only problem. Why, for example, do Europe's cradle-to-grave entitlements so often end up encouraging declining populations, atheism and lower worker productivity that is readily apparent to the casual visitor?

Perhaps if everybody ends up about the same, regardless of effort or achievement, then life must be enjoyed mostly in the here and now. Why sacrifice for children, or put something aside for heirs, or worry over a judgment in the afterlife? The more the European Union talks about its global caring, the less likely its own citizens are to have children.

It is also strange that the more Europeans flock to their ancient majestic cathedrals, splendid museums and grandiose villas and castles to satisfy an innate human desire to enjoy artistic, architectural and religious achievement, the more it is likely that they would never again build a now politically incorrect cathedral at Rouen, a Schonbrunn Palace or a castle on the Rhine.

Much is made of European multiculturalism, a willingness to allow Muslims from the Middle East, Pakistan and Turkey to live separate lives without assimilating fully into European society.

But such "tolerance" reflects in part a fear of radical Islam and terrorism. For all the European talk of progressive attitudes about free speech, feminism and gay rights, such principles fade quickly when radical Muslims demand Sharia law, demonize homosexuals or threaten European cartoonists and novelists. It is almost as if the more Europe takes pride in its own multiculturalism, the larger its ethnic ghettoes expand — and the more its native populations grow bitter against the foreign-born.

Europe is a vocal member of the United Nations and other transnational organizations. But this utopian internationalism depends on the protection guaranteed by the United States and its huge military. Otherwise, there would either be costly European militaries — or the occasional threat of attack. Europeans forgot that just because they are not looking for war, it doesn't mean that war might not look for them.

In short, as a reaction to the self-destruction of Europe in World War II and the twin monsters of fascism and communism, Europeans thought they could change human nature itself through the creation of an all-caring, all-wise European Union uber-citizen. Instead of dealing with human sins, European wise men of the last half-century would simply declare them passi.

But human-driven history is now roaring back with a fury in Europe — from Mediterranean insolvency, to the threat of radical Islam, to demographic decline, to new international dangers on the horizon.

Only one question remains: At a time when Europe is discovering that its democratic socialism does not work, why is the United States doing its best to copy it?