It's a highly admirable thing, really: Opponents of Obamacare say they are rising to defend liberty.

In this case, it's economic liberty. There's no way, they say, that Congress has the power to make people buy something they don't want to buy, like health insurance. Thirteen states, including Texas, have raised that claim as part of a federal lawsuit meant to block implementation of the new health care law so strongly backed by President Barack Obama.

They're absolutely correct when they say the Constitution is supposed to protect liberty -- or more precisely, to "secure the blessings of liberty to ourselves and our posterity," as its preamble says.

But as strongly as they might want to fight the good fight, their odds of getting what they want are not good under the Supreme Court's modern-day take on the Constitution. That doesn't mean that they can't cause an about-face; it's happened before. But their challenge is nothing less than to reverse more than 70 years of legal precedent that favors Obamacare and the way it is being implemented.

Legal scholars examined the new law's "individual mandate" to buy insurance for months as the health care overhaul was debated on the presidential campaign trail and then in Congress. Some of them point to the part of the Fifth Amendment that says no person may be "deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation."

Mark Hall, a professor at Wake Forest University's law school and an expert in health care law and policy, was blunt in his analysis: "Under the Due Process Clause, no Supreme Court decision since 1935 has struck down any state or federal legislation for infringing economic liberties, and any such action would be radically inconsistent with current constitutional doctrine."

Of course, no guardian of liberty has to listen to a law professor.

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