So far as I know, no neurosurgeon has ever written a book about the U.S. Constitution. But then again, no neurosurgeon has ever made a serious run for the presidency. Combining personal graciousness and plain exposition with some wild right-wing clichés, Ben Carson's slim volume tells us a lot about the sources of his appeal. Like the man himself, the book is not what you might expect.

Carson is unmistakably outraged by the direction in which the U. S. has been heading. "Our nation," he writes, "is in such shambles that it appears that almost anyone could do a better job of execution than the current leaders." It would have been easy for him to take the well-trodden path of those who share that view. Some popular books on the Constitution tell a terrifying tale of betrayal, in which Democrats (and President Barack Obama in particular) have run roughshod over the framers' handiwork in order to create a kind of empire.

Carson has evident sympathy for that account, but his approach is far more measured and less polemical. His main goal is education and exposition, not conversion. Much of the book consists of simple summary.

Curious about the thirteenth amendment? It "ended slavery and involuntary servitude in the United States and all its territories." (True.) Interested in the twenty-second amendment? "After Roosevelt's death, Americans worried that he had set a bad precedent, and Congress proposed a term-limit amendment." (Essentially right.) The qualifications for president?  You have to "be a natural-born citizen, be at least thirty-five years old, and have been a resident of the United States for at least fourteen years." (Right again.)

But in his unfailingly low-key manner, Carson has some amazing things to say. He appears to think that the Constitution forbids progressive taxation, because the founders "didn't mean that the government should take money from one group to support another group." In his account, "a flat tax may be the only tax that truly treats everyone fairly and thus promotes the general welfare." In the view of some tax reformers on the right, maybe so, but as a claim about constitutional law, that's pretty far-fetched.

With respect to abortion, Carson gestures toward the plausible idea that state governments should be allowed to decide the issue as they like. But his real conclusion is far more radical. Because children's lives are at stake, the Constitution actually forbids abortion:  "No ruling that allows the killing of children can be in line with the Constitution's stated purpose of 'secur[ing] the Blessings of Liberty to ourselves and our Posterity.'" Welcome back to the land of the far-fetched. No member of the Supreme Court has ever argued that the Constitution requires states to ban abortions.