America's Population Set to Top 300 Million

In Los Angeles, the nation's most densely populated metropolitan region and its most heavily Latino area, 300 million will be yet another confirmation that congestion is out of control, Myers predicted.

"I don't think people view population growth as a plus anymore," he said, noting that Angelenos are punished by it "every single day" when they go out in freeway traffic.

The 300-million milestone, it should be noted, is an educated guess by the Census Bureau, not an actual people count. It emerges from a formula that crunches births and new immigrants against deaths. The 300-millionth person, therefore, will never win a trip to Disneyland because he or she will not be identified.

The 100-million markers are also coming more quickly. From the Declaration of Independence in 1776, it took the country 139 years to get to 100 million in 1915, then 52 more years to reach 200 million in 1967 and 39 more years to hit 300 million. The 400 million mark, according to census projections, will be reached in about 37 years. That, of course, could change if the current anxiety about immigration were to result in the closing of the country's borders. Without immigration, the U.S. population could go into a European-style stall.

It was a change in immigration law in 1965, when Congress abolished a national-origins quota system, that unintentionally reignited immigrant-led population growth, according to William H. Frey, a demographer with the Brookings Institution. "It made family reunification an important criteria for immigration and it led to a chain reaction of higher fertility," he said.

The relative presence of immigrants, about 12 percent of the total population, is more than double what it was when the population topped 200 million. Immigrants are also more visible than ever, having fanned out from gateway cities such as New York and Los Angeles to parts of the rural South and Midwest where they had not been seen in substantial numbers before. Still, the foreign-born share of the population remains lower than between the melting-pot years of 1860 and 1920, when it was about 14 percent.

Many demographers believe it is shortsighted to be anxious about the 300-million marker. They regard it as a symbol of an economically dynamic democracy that remains popular in much of the world.

"As almost nothing else can, immigration-led growth signals the attractiveness of the American economy and polity," said Kenneth Prewitt, a former head of the Census Bureau and now professor of public affairs at Columbia University. "You don't see large numbers of immigrants clamoring to move to China."

Indeed, lots of good news is embodied in the lives of the 300 million. Longevity has jumped from 55 years in 1915, to 71 years in 1967, to 78 years now. Over that time frame, the percentage of the adult population with a high-school diploma has jumped from 14 percent to 85 percent. Homeownership has risen from 46 to 69 percent. The death rate from tuberculosis has fallen from 140 to 0.2 per 100,000 people. While houses are 4.5 times as expensive (in constant dollars) as they were in 1915 and twice as expensive as in 1967, a gallon of milk in 2006 costs less than half what it went for in 1915 and in 1967.

After this year's election rhetoric cools, Frey hopes that Americans will see a silver lining in immigration: Foreign-born residents and their children will surge into the workforce, and their payroll taxes will help reduce funding shortfalls for Social Security and other social programs that benefit older people.

"So many middle-aged baby boomers who oppose immigration may be biting the hand that could feed them," Frey said.

This assumes, though, that immigrant children, especially Hispanics and blacks, will be educated well enough in American schools to find competitive jobs in the global economy.

Poverty rates for children have exceeded poverty rates for the elderly for more than 40 years, according to Linda A. Jacobsen, director of domestic programs at the Population Reference Bureau, a nonpartisan research group.

Hispanic and black children are between three and four times as likely to live in poverty as whites, so their growing numbers may not translate into growing national wealth. In addition, the divide between aging baby boomers in retirement and the younger workers who are supporting them with payroll taxes will have a racial, as well as a generational, dimension.

"Unless we can reduce age, racial and ethnic disparities in poverty," Jacobsen warns, "children from minority groups may be less able and less willing, as they grow up, to support the predominantly white elderly population."