The Times reports that Mitch McConnell will bring to the floor a bill that would ban abortions after 20 weeks.

One thing that will prove popular among the base is a commitment by Senator Mitch McConnell, the presumptive new majority leader, to bring up a bill that would ban abortions after 20 weeks of pregnancy, which he is expected to do next year.

That bill has a 0% chance of passing, but let’s assume a Republican President in 2016 signs it into law. Would this bill be constitutional? Let’s put aside the Due Process angle, and focus on the Commerce Clause and Section V of the 14th Amendment.

You may recall that in Gonzales v. Carhart, Justice Thomas concurred separately with Justice Scalia to note that the Partial-Birth Abortion ban may have been susceptible to a commerce clause challenge, but because the parties did not raise it, the issue was waived. Presumably, the Justices would have invalidated the bill on those grounds.

Would the challengers make an argument that such a law exceeds Congress’s powers under the Commerce Clause or Section V of the 14th Amendment? On the one hand, I suppose they would want to make any argument possible in order to invalidate the law. On the other hand, it would be very tough for groups like the ACLU or Planned Parenthood to line up behind an argument that places a significant limitation on federal power, over something as commerce-y as health care. Don’t forget the ACLU favorably cited Jacobson v. Massachusetts in their Obamacare brief. Priorities.

Imagine a 5-Justice bloc that would invalidate the law on commerce clause grounds, and another 5-Justice bloc that invalidates it on due process grounds, with AMK in the middle. That’s about right.