Einer Elhauge is a professor at Harvard Law School. He joined an amicus brief supporting the constitutionality of the mandate.

In making the legal case against Obamacare’s individual mandate, challengers have argued that the framers of our Constitution would certainly have found such a measure to be unconstitutional. Nevermind that nothing in the text or history of the Constitution’s Commerce Clause indicates that Congress cannot mandate commercial purchases. The framers, challengers have claimed, thought a constitutional ban on purchase mandates was too “obvious” to mention. Their core basis for this claim is that purchase mandates are unprecedented, which they say would not be the case if it was understood this power existed.

But there’s a major problem with this line of argument: It just isn’t true. The founding fathers, it turns out, passed several mandates of their own. In 1790, the very first Congress—which incidentally included 20 framers—passed a law that included a mandate: namely, a requirement that ship owners buy medical insurance for their seamen. This law was then signed by another framer: President George Washington. That’s right, the father of our country had no difficulty imposing a health insurance mandate.

That’s not all. In 1792, a Congress with 17 framers passed another statute that required all able-bodied men to buy firearms. Yes, we used to have not only a right to bear arms, but a federal duty to buy them. Four framers voted against this bill, but the others did not, and it was also signed by Washington. Some tried to repeal this gun purchase mandate on the grounds it was too onerous, but only one framer voted to repeal it....