"While voting is always a moral obligation, sometimes that obligation is stronger than at other times. This is especially true when pro-life people have an opportunity to elect, in a close race, someone who is committed to protect the unborn, and remove from office someone who isn't. It is also true when the balance of power in a legislative body can be changed by the election.
We have a moral obligation to vote in such a way that will do the most to advance the culture of life."
"You may in some circumstances where you don't have any candidate who is proposing to eliminate all abortion, choose the candidate who will most limit this grave evil in our country, but you could never justify voting for a candidate who not only does not want to limit abortion but believes that it should be available to everyone."
"Except in the case in which a voter is faced with all pro-abortion candidates (in which case, he or she strives to determine which of them would cause the least damage in this regard), a candidate that is pro-abortion disqualifies himself from receiving a Catholic's vote. This is because being pro-abortion is intrinsically evil and cannot be morally justified for any reason or set of circumstances. To vote for such a candidate even with the knowledge that a candidate is pro-abortion is to become an accomplice in the moral evil of abortion. If the voter also knows this, then the voter sins mortally."