Similarly, the ban on intact D&E, which accounts for a tiny share of abortions, in itself will not have much impact on the practice of medicine. But it opens the door to a wide variety of laws through which members of Congress can substitute their medical judgment for that of physicians throughout the country.
Medicine advances largely as a result of disputes about the hazards and benefits of different treatments that are resolved over time by clinical experience and research. If Congress decides to resolve these arguments by legislative fiat instead -- dictating, say, that bariatric surgery is an unacceptably dangerous treatment for obesity, or that radiation is better than chemotherapy for breast cancer -- it will short-circuit this process, replacing science with politics.
Such meddling is unconstitutional as well as unwise. The constitutional pretext for the Partial-Birth Abortion Ban Act, as with so much else that Congress does, is the authority to regulate interstate commerce. But if an abortion qualifies as interstate commerce, it's hard to see how anything is beyond the federal government's purview.
"Whether the Act constitutes a permissible exercise of Congress' power under the Commerce Clause is not before the Court," Justice Clarence Thomas noted in his concurring opinion. Instead of discussing the right to abortion, the Court should have been questioning Congress' authority to regulate the practice of medicine, which is equally hard to find in the Constitution.