First it turns out that legal abortion fights crime by reducing the number of future criminals.
Then it turns out that legal abortion reduces abortion (no, that’s not a typo) by reducing the number of future aborters.
And now it may turn out that legal abortion changes electoral outcomes by reducing the number of future Democrats.
This last is an article by a conservative (originally published in the American Spectator), so naturally the spin is that the Democrats are wrong on the abortion issue and paying for it at the ballot box. I don’t think the Democrats are wrong on abortion, but I think the numerical analysis makes a lot of sense (though I haven’t checked it carefully). If it seems like Democrats are making a strategic error by supporting abortion, notice that the very same argument shows a mirror-image error in Republican strategy. If the Republicans ever succeeded in banning abortion, they would be contributing to the ranks of the Democratic party.
UPDATE: Read my more careful analysis and partial recantation here.