What is the price tag for legalizing millions of undocumented immigrants? Would it increase the country’s coffers – or drain them?

As with many aspects of the debate on immigration, the answer depends on where people stand on what to do with the nation’s estimated 11 immigrants.

Those who oppose making legalization a part of any comprehensive immigration reform measure say that doing so would be financially detrimental because – since the majority have little education and are low-skilled, this group says -- they would place more burden on public assistance rolls.

“People with low income get more out of Social Security than they pay in,” said Mark Krikorian, executive director of the Center for Immigration Studies, a think tank advocating curbing legal and illegal immigration. “State and localities will extend benefits, they would pick up a lot of the slack and pay out of their own treasuries.”

On the other hand, groups that favor providing a path to legalization say immigrants who are brought out of the underground economy and out of the shadows will end up contributing more dollars than they will use in services.

Clarissa Martinez of the National Council of La Raza, a national immigrant advocacy group, said that legalization most likely would prove more financially beneficial than harmful to the United States.

“Most economists who have looked at the issue have come up on the side that it would be a net gain, and that making them [an official] part of the workforce would not hurt workers because they would be complementary to the U.S. workforce.”

Researchers and scholars who have examined the issue aren’t any more united in their conclusions on the matter than groups who advocate for or against a pathway to legalization, and expanding the country’s existing – and widely derided – guest worker program.

Robert Rector, a researcher with the Heritage Foundation, a conservative think tank, says that comprehensive reform proposals that have been introduced by President Obama and a bipartisan Senate group could cost trillions, to a great extent because of what he expects would be the heavy use of public assistance by millions of immigrants-turned-citizens.

“It’s not like they pay in a lot when they are young,” he told The Daily Caller, a conservative news website, in an interview in January, “and they take it out when they’re old. They are in fiscal deficit every year of their lives.”

Rector also raises concerns about the president’s health care reform program, which is off limits to undocumented immigrants. He and other critics of legalization say that it would make millions suddenly eligible to be part of the insurance program.

But immigrant advocates long have argued that undocumented immigrants, unable to afford medical care, end up turning to more costly alternatives, such as hospital emergency rooms. And then there are the intangible costs, they say, such as the health danger they pose to their communities by, for example, not getting vaccinations or treating infectious conditions.

“Critics are selective when they talk about these immigrants’ contributions, and very expansive when they talk about what they would cost,” Martinez said. “They talk about how these immigrants and their kids would add to the costs. But many of them have U.S. citizen kids, who already are eligible for services. And they don’t take into account that having access to healthcare, and preventative care, is better.”

Gordon Hanson, a University of California professor who often writes about immigration and the economy, agreed that legalizing them would be more economically prudent than leaving them off the radar.

“True, many of these workers are in the country illegally,” he wrote in a report on the cost of undocumented immigration. “Approximately three-fifths of immigrant workers with less than a high school education are undocumented. Yet, their mobility across jobs and zip codes helps smooth fluctuations in the U.S. economy and ease the burden on U.S. workers when the unemployment rate rises.”

Hanson conceded that legalizing them, and making them an official part of the workforce, could hurt some U.S. workers.

“If low-skilled immigration pushes down wages for low-skilled labor, U.S. employers gain and U.S. low-skilled workers lose, with the gains to the former offsetting the losses to the latter," he said. "Moreover, economic theory suggests that immigration generates a surplus by making capital and land more productive, meaning that gains to U.S. employers are likely to exceed any losses to U.S. workers.”

Many on both sides agree on this much – like so many aspects of immigration, this one is complicated.

So much is still speculative, they say, regarding cost versus benefits. It’s a population that’s largely in the shadows. And there still is no immigration reform bill that would make it easier to get a better handle of the costs.

“There are so many moving parts in this,” Krikorian said. “Trying to get reasonable numbers is hard.”

And, to be sure, Krikorian said, there are reasons, even if there are costs, to legalize some undocumented immigrants, such as DREAMers -- undocumented immigrants who were brought as minors.

“The cost is not enough of a reason not to do it,” he said, referring to legalization. “If it’s in the national interest, then the cost is just the cost. The DREAM Act kids we just legalize. They're more educated, so the cost of legalizing them would be small, and they might just pay more in taxes than they use in services."

And besides, he said, "Their identities were formed here. That cost or benefit is irrelevant."

Elizabeth Llorente can be reached at elizabeth.llorente@foxnewslatino.com

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