Not really. For example abortion. Since the overwhelming women having abortions are Liberals, the more abortions the bigger reduction in "the pool of Liberal voters"
Of course social liberalism creates more liberal voters, we have 60 years of history that makes that obvious, don’t look to abortion to eliminate the voters that social decay and social liberalism creates more of, abortion just kills babies.
Everything else being equal, yes.
But consider for instance that the disproportionate numbers of abortions by black women (Liberals) is being offset by the mass importation of Hispanics (Liberals). You don’t have a net reduction in the numbers of Liberal voters, just a slowing in their rate of growth.