The conservative economist Milton Friedman famously said, “You can’t have free immigration and a welfare state.” He was right. You can’t flood our labor markets with illegal workers paying little in taxes – and provide good government benefits for everyone.

But perhaps the opposite also is true. Perhaps you can’t have open borders if you have a high level of benefits.

That’s the case in Canada and much of Europe. Canada has a large immigration program and guaranteed health care for everyone, including foreigners who are legal residents. Canada does not tolerate illegal immigration. It can’t afford to extend its expensive benefits to people who don’t belong there.

Conservative politicians often portray government programs as a magnet to illegal aliens, but almost never as an incentive to enforce America’s immigration laws. Rep. Sam Graves, a Missouri Republican, last year voted against the popular bill to expand the Children’s Health Insurance Program. This would have helped more moderate-income families cover their uninsured children. When his Democratic foe, Kay Barnes, slammed him over the vote, Graves responded that the bill would have extended “free taxpayer-funded health care” to, among others, illegal immigrants.

Funny thing about “taxpayerfunded health care,” which, by the way, no one should ever call “free.” Billionaire retirees get it, as do the poor and members of Congress, including Graves and his kin.

Other Americans obtain private coverage through their employer or can buy their own, assuming they don’t have a sick family member. The only large uninsured group that doesn’t have health care security is the working stiffs.

And what about illegal immigrants? They don’t have a government program, but they can show up in the nation’s emergency rooms. The care delivered there may be “free” for them, but is subsidized by the taxpayers and by higher premiums on private health insurance.

In this country, threadbare government benefits are an essential element of the cheap-labor economy. Illegal immigrants provide low-cost labor and suppress the wages of workers who must compete with them, be they native-born or legal immigrants.

And as long as few benefits are flowing to them from Washington, the Bush administration can offer this gift to employers with little skin off its own back. Those who do pay most of the resulting costs are unskilled workers and the local governments that must provide services to people who contribute little to their coffers.

But suppose the federal government guaranteed health coverage for all workers and their families. Wouldn’t that make open borders far more expensive? It would.

Democrats have just dropped plans for another vote on the Children’s Health Insurance Program. Bush had condemned the bill as a perilous move toward “government-run health care for every American” – and has promised to veto the legislation as he’s done twice before. (Bush’s concern about government-run enterprises must have had them rolling in the aisles on Wall Street this week, as the U.S. Treasury effectively nationalized the two financial companies responsible for three-quarters of new home mortgages.)

Singling out 10 million working-class children as the one group unworthy of a government insurance program would seem beyond the moral pale, but the Bush administration has always had a warped idea of right and not right. As for the immigration angle, the bill wouldn’t have covered legal aliens, much less illegal ones.

But beyond those particulars lies this argument: The more generous the social safety net, the more essential that the people using it are here legally and making enough money to help pay the costs. Milton Friedman didn’t like government, but he would have gotten the point.