Doubly Hispanic; vastly more Asian; equivalently African American; much less white. Overall: Older.

The makeup of the United States is expected to alter dramatically by mid-century, with immigrants and their U.S.-born descendants accounting for virtually all the population growth and demographic changes, the Pew Research Center said in a report released yesterday.

The study, by the Washington group that calls itself a nonpartisan fact tank, used 2005 as its base year and projected to 2050.

"If current trends continue, the population of the United States will rise to 438 million in 2050, from 296 million in 2005, and 82 percent of the increase" will be immigration-related, the authors wrote.

Of the 117 million people who would be added to the United States because of immigration through 2050, 67 million would be new immigrants and 50 million would be their American-born children and grandchildren, the study found.

The Latino population is already the largest minority group, 14 percent of the population in 2005. By 2050, it was projected to be 29 percent.

Asians were projected to increase from 5 percent to 9 percent; non-Hispanic whites, currently 67 percent of the population, would decrease to 47 percent.

Another key finding concerned the nation's future "dependency ratio" - the number of children and people 65 or older compared with the number of working-age Americans, ages 18 to 64.

There were 59 children and elderly people per 100 working-age adults in 2005. That was projected to rise to 72 dependents per 100 adult workers in 2050.

In the context of the national debate about illegal immigration policy, the Pew presenters adhered to their practice of deflecting direct questions about the study's inferences.

"Over the long sweep of our history, immigration rates have gone up and down. We try to inform these debates" but not take positions, Pew Research Center executive vice president Paul Taylor said in a conference call.

Jan Ting, a former assistant commissioner with the Immigration and Naturalization Service who teaches a course on Citizenship, Immigration and Refugees at Temple University's Beasley School of Law, thinks the most stunning finding of the report is its population projection.

"The most troubling aspects," he said, "are the implications . . . on schools, the notion of universal health, our criminal-justice system, our infrastructure, our environment."

Ting interpreted the report as a reason to crack down on illegal immigration. The report makes no distinction between documented and undocumented entry.

"If we can address the illegal portion and reduce it somehow, we can put the brakes on this sort of growth, and hopefully not get to the scenario" that Pew outlines, he said.

As for the suggestion that immigrants, because most of them are of working age, will help ease the burden of the increased dependency rate, Ting was doubtful, especially if the immigrants are documented.

"If we give them a pathway to citizenship, these people are going to be able to bring their parents over. Any benefit that we get from having this young workforce will be offset," he said.

John Fonte, a senior fellow at Washington's Hudson Institute, where he directs the Center for American Common Culture, said he believes the nation is experiencing "an assimilation crisis" that could intensify by mid-century.

If Pew's projections are correct, he said, "we should get even more serious about ending anti-assimilation measures."

"We have bilingual ballots. We have bilingual education. We have dual citizenship voting. All of these things are clashing" with what it means to have an American identity, he said.

As for the policy implications of the Pew report, "the levels of immigration ought to be connected to how well we are doing with assimilation. Since we are not doing so well right now, I would decrease it."

Varsovia Fernandez, executive director of the Greater Philadelphia Hispanic Chamber of Commerce - 300 business owners and Latino professionals - said the Pew study seemed like a good argument for committing more educational resources to Hispanics, whose high school graduation rates are below 50 percent.

"What it tells me is that we really need to giddy-up and start paying more attention.

"If the workforce of the future is going to be a lot more Hispanics," she said, "we need to do a better job of educating them."

Read the Pew Research Center's report (.pdf) via