MONTERCHI, ITALY – It was a lovely summer evening. Large families filled the terrace at La Pieve Vecchio, a restaurant occupying an old convent on the outskirts of this hilltop village in Tuscany. Some groups even included small children, perched in high chairs or wandering the dining area with an anxious parent trailing close behind.

That's a common scene in America but not in Europe, especially in Italy. Here, children are almost as rare as the truffles that were in high season and featured on La Pieve's menu. And that birth dearth is causing a crisis across the continent.

"As if it did not have enough problems with its never-ending fiscal and economic crisis," notes international economist Paolo von Schirach, "Europe is also afflicted by long-term, possibly terminal, demographic decline."

The impact of this decline has "already had noticeable effects, none of them good," he explains. Lower birth rates lead to aging populations, fewer young people in the workforce and a shrinking tax base.

As the New York Times recently reported from Germany, "Europe's plunge in fertility rates over the decades (presents) a problem that has frightening implications for the economy and the psyche of the Continent."

The problem is particularly acute here in Italy, where the average birth rate is 1.39 children per female, far below the 2.1 needed to keep the population stable. "The number of great-grandparents is overtaking the number of great-grandchildren," according to the Aspen Institute Italia, "and in addition to an increase in the number of people over 65, Italy is also seeing a rise in over 80-year-olds."

This is not a new story; European birth rates have been dropping for many years. But the perspective from Monterchi offers an important insight into the immigration reform debate that has paused for August back in Washington but will resume in the fall.

Yes, Americans are somewhat more fertile than Europeans, but the United States has something else that is just as valuable to the economy as children. Foreigners.

Proponents of immigration reform have focused on the enormous economic benefits contributed by newcomers --starting new businesses, inventing new products, filling jobs others don't want. But they also foot the nation's bills. They help alleviate the "frightening implications for the economy" posed by an aging population that uses more services and pays fewer taxes.

Sure, the United States is running huge budget deficits, but our fiscal problems are far less severe than those in Europe, and immigrants are one key reason.

We did see some foreigners here in Italy, and not just tourists. Our server at La Pieve was a young woman from Poland; another waiter told us he'd come from Romania with his mother. In the marketplace at nearby Umbertide, several vendors wore the hijab, a Muslim head scarf.

But Europe has far more trouble than America does in attracting and assimilating hardworking, bill-paying young immigrants. These are still largely homogenous countries that lack the diversity and tolerance that has always marked the New World culture.

True, America has frequently exhibited a streak of xenophobia, or fear of foreigners, that focuses today on Latinos and Muslims. But there's no Statue of Liberty welcoming newcomers to Rome or Paris or Berlin. And when they do come to Europe, immigrants are less likely to settle down and become part of the community.

The word "xenophobia" is originally Greek, not English. A Somali working in the market at Umbertide will never be truly Italian, while an Italian who opens a bakery in Cleveland can eventually become a full-bodied, flag-waving American.

Faced with this "demographic decline," European governments are struggling for answers. Some have provided lavish subsidies to young couples to bear more children. Others are trying to convince women to join and stay in the workforce. But these goals can be contradictory, especially for traditional European cultures that have "long glorified stay-at-home mothers," notes the Times.

"Another way to adjust to the population decline is to get older workers to postpone retirement," the Times added. For example, "Volkswagen has redesigned its assembly line to ease the bending and overhead work that put excessive strain on workers' bodies."

Europe would be far better off if it had young immigrants to do all that bending and reaching -- and to pay taxes on their earnings. They don't, but the United States does. And that's why the message from Monterchi is clear: America should encourage more immigrants and legalize the ones who are already contributing to our economic vitality.

Steve and Cokie Roberts can be contacted by email at stevecokie@gmail.com.