President Obama's health-care bill is now moving toward final passage. The policy issues may be coming to an end, but the legal issues are certain to continue because key provisions of this dangerous legislation are unconstitutional. Legally speaking, this legislation creates a target-rich environment. We will focus on three of its more glaring constitutional defects.

First, the Constitution does not give Congress the power to require that Americans purchase health insurance. Congress must be able to point to at least one of its powers listed in the Constitution as the basis of any legislation it passes. None of those powers justifies the individual insurance mandate. Congress's powers to tax and spend do not apply because the mandate neither taxes nor spends. The only other option is Congress's power to regulate interstate commerce.

Congress has many times stretched this power to the breaking point, exceeding even the expanded version of the commerce power established by the Supreme Court since the Great Depression. It is one thing, however, for Congress to regulate economic activity in which individuals choose to engage; it is another to require that individuals engage in such activity. That is not a difference in degree, but instead a difference in kind. It is a line that Congress has never crossed and the courts have never sanctioned.

In fact, the Supreme Court in United States v. Lopez (1995) rejected a version of the commerce power so expansive that it would leave virtually no activities by individuals that Congress could not regulate. By requiring Americans to use their own money to purchase a particular good or service, Congress would be doing exactly what the court said it could not do.

Some have argued that Congress may pass any legislation that it believes will serve the "general welfare." Those words appear in Article I of the Constitution, but they do not create a free-floating power for Congress simply to go forth and legislate well. Rather, the general welfare clause identifies the purpose for which Congress may spend money. The individual mandate tells Americans how they must spend the money Congress has not taken from them and has nothing to do with congressional spending.