We Americans don't seem to worry that we owe billions of dollars to the Chinese, or that our oil hunger is enriching hostile rogue regimes, or that our annual budget deficit keeps adding to our national debt.

Why fret now? For nearly a quarter-century, Americans have come to expect the good life. Unemployment should never go above 5 percent. Interest rates are expected to be always around the same low percentages, inflation even lower — and all this accompanied by steady growth in the economy and expanding government entitlements. Double-digit rates of interest, unemployment and inflation — the stagflation that characterized the Nixon and Carter administrations — are apparently ancient history.

Along with the amazing performance of the post Cold-War economy, technology has made the basics of life far more enjoyable — cell phones, the Internet, high-definition cable television, iPods and the like. The entrance of 2 billion workers in China and India into the global capitalist system, along with easy credit, makes material goods more accessible to the consumer than ever.

Luxury is now available to the middle class. Magazines are devoted to remodeling kitchens with granite tops and tony stainless steel appliances. Suburban tract houses often have both hot tubs and gardeners. Garages now appear in new developments with not one but two garage doors — and on occasion three or even four.

What are the consequences of this affluence?

For starters, a certain lack of appreciation of our bounty. No one praises Reagan, Clinton or the current President Bush for the past amazing performance of the U.S. economy. Instead, it's taken as America's new birthright.

We expect almost instantaneous success in everything we do. Most in the media are thus tired of the present wars in the Middle East and think the enormous human cost is not worth the goal of offering freedom to millions, even though we have suffered far fewer fatalities in Iraq and Afghanistan than a generation sacrificed in Vietnam.

As we near the fifth anniversary of Sept. 11, most have forgotten the dangers of a terrorist attack. Often the public appears to worry more over the Patriot Act and wiretaps, as if our own leaders pose a greater threat to the United States than do mass-murdering Islamist terrorists.

But could our good life really sometime come to an end — as the histories of past affluent societies suggest it will? Imagine al-Qaida attacking the New York Stock Exchange or an unexpected North Korean missile taking out a West Coast city. What if Beijing suddenly had to sell off billions of its accumulated American dollars? Or how about a good old 1970s-style recession in which interest rates hit 20 percent, with inflation and unemployment each hovering near 10 percent? What would millions of younger Americans do — people who have known only the prosperity, material surfeit and mostly peace and security of the 1980s and 1990s?

Prosperity can also be deceiving. Many Americans, despite superficial affluence, are in debt and often a paycheck away from insolvency. By historical standards, they are pretty helpless. Most of us can't grow our own food, don't know how cars work and have no clue where or how electricity is generated. In short, few have the smarts to survive if the thin veneer of civilization were to be lost, as it has been from time to time in places like downtown New Orleans.

Think back to the Roman era of the "Five Good Emperors" — between A.D. 96-180 under the reigns of Nerva, Trajan, Hadrian, Antonious Pius and Marcus Aurelius — when all problems of the turbulent past at last seemed to have been solved. There was a general peace, ever more prosperity from Mediterranean-wide trade, and a certain boredom and occasional cynicism among the Roman elite. Few then had any idea that three centuries of war, revolution, poverty and scary emperors like Commodus and Caracalla awaited their descendants — all a prelude to a later general collapse of Roman society itself.

In our own new age of war, terrorism, huge debt, high-priced gas and frightful weapons and viruses that we try to ignore, we should remember that civilization's progress is not always linear. The human condition does not inevitably evolve from good to better to best, but always remains precarious, its advances cyclical.

The good life sometimes can be lost quite unexpectedly and abruptly when people demand rights more than they accept responsibilities, or live for present consumption rather than sacrifice for future investment, or feel their own culture is not particularly exceptional and therefore in no need of constant support and defense.

We should tread carefully in these challenging days of our greatest wealth — and even greater vulnerability.

Victor Davis Hanson is a classicist and historian at the Hoover Institution at Stanford University. Reach him at author @victorhanson.com.