Is the mandate to buy health insurance constitutional?

In an important recent speech, Senator Max Baucus claims that there is a broad consensus among legal scholars (that the individual mandate is constitutional. He claims that "those who study constitutional law as a line of work have drawn th[e] same conclusion" as congressional Democrats. Similar assertions have been made in parts of the liberal blogosphere. For example, Think Progress denounces Republican Senators Ensign and DeMint for citing only "right-wing think tanks" in support of their claims that the mandate is unconstitutional, and chides them for supposedly being unable to cite "a single judge, justice or reputable constitutional scholar who believes that health reform is unconstitutional."

There certainly are prominent constitutional law scholars who agree with Baucus. But the claim that there is an overwhelming expert consensus on the subject is simply false. As co-blogger Jonathan Adler points out, Baucus mistakenly cited him as a scholar who agrees with the Democrats' conclusions even though he actually believes that the mandate is not constitutional. The "right-wing think tank" study cited by Ensign and DeMint was actually coauthored by co-blogger Randy Barnett, one of the nation's most prominent constitutional law scholars, and an expert on the original meaning of the Commerce Clause (the provision usually cited as authorizing Congress to impose the mandate). Richard Epstein of NYU and the University of Chicago is another prominent legal scholar (one of the ten most cited in the country) who believes that the mandate is unconstitutional.

I certainly wouldn't put myself on the same plane as Jonathan, Randy, or Richard Epstein. But I'm a professional constitutional law academic, federalism and the Commerce Clause are among my areas of expertise, and I think the mandate is unconstitutional too.