Texas Gov. Rick Perry has been beaten up in recent GOP presidential primary debates over his signing of a bill in 2001 giving in-state tuition to illegal immigrant kids in Texas. Look for the issue to come up again at tonight’s debate in New Hampshire.

In a free society, so-called DREAM Act legislation would be unnecessary. Opportunities for legal immigration would be open wide enough that illegal immigration would decline dramatically. And higher education would be provided in a competitive market without state and federal subsidies. But that is not yet the world we live in.

On the federal level, the proposed Development, Relief and Education for Alien Minors Act would offer permanent legal status to illegal immigrant children who graduate from high school and then complete at least two years of college or serve in the U.S. military. Legal status would allow them to qualify for in-state tuition in the states where they reside, and would eventually lead to citizenship.

Those who respond that such a law would amount to “amnesty” for illegal immigrants should keep a couple of points in mind.

First, kids eligible under the DREAM Act came to the United States when they were still minors, many of them at a very young age. They were only obeying their parents, something we should generally encourage young children to do.

Second, these kids are a low-risk, high-return bet for legalization. Because they came of age in the United States, they are almost all fluent in English and identify with America as their home (for many the only one they have ever known). “Assimilation” will not be an issue.

They also represent future workers and taxpayers. The definitive 1997 study on immigration by the National Research Council, The New Americans, determined that an immigrant with some college education represents a large fiscal gain for government at all levels. Over his or her lifetime, such an immigrant will pay $105,000 more in taxes than he or she consumes in government services, on average and expressed in net present value (see p. 334). In other words, legalizing an immigrant with post-secondary education is equivalent to paying off $105,000 in government debt.

According to estimates by the Immigration Policy Center, the DREAM Act as introduced in 2009 would offer immediate legalization to 114,000 young illegal immigrants who have already earned the equivalent of an associate’s degree. Another 612,000 who have already graduated from high school would be eligible for provisional status and would then have a strong incentive to further their education at the college level to gain permanent status. If all 726,000 of them studied at college and became legal permanent residents, it would be equivalent to retiring $76 billion of government debt.

In all, a potential 2.1 million kids could eventually be eligible for permanent legal residency under terms of the DREAM Act, representing a potential fiscal windfall to the government of more than $200 billion. Not to mention their potential contributions to our culture and economy.