Moreover, Alito pointed out that the standard Roberts informally proposed, that perhaps abortion could be banned after a reasonable period has elapsed, would have forced the Supreme Court back into the position of drawing arbitrary lines that it never had any business drawing in the first place.

“For example, if the period required to give women a ‘reasonable’ opportunity to obtain an abortion were pegged, as the concurrence seems to suggest, at the point when a certain percentage of women make that choice, we would have to identify the relevant percentage,” Alito said. “It would also be necessary to explain what the concurrence means when it refers to ‘rare circumstances’ that might justify an exception.”

In my view, Roberts’s “compromise” approach would have been the worst of all worlds. It would have maintained an unacceptable ambiguity around abortion, tying the issue up in the courts for years more. Legislatures would have continued a game of blind man’s bluff, passing laws restricting abortion whose constitutionality they could not necessarily guarantee, then waging lengthy court battles that would eventually wind their way toward Washington to be decided by the Supreme Court.