Some will argue that this is Church interference with political matters. Generally, public policy isn't within the competence of the Church, or more accurately, within the infallible teaching authority of the Church.
But abortion as a political issue isn't comparable to other matters of public policy, like Social Security, welfare, environmental regulation and the like. These issues fall within the realm of prudential judgement, and should generally be left to statesmen to decide. Abortion is intrinsically evil, and is never morally permissible (except in the rare case where a mother's life may be endangered).
I thought abortion isn't even permissible under those circumstances (the life of the mother)?