Pretty much laying it on the line here, isn’t he?

I would say, “Give consideration to your eternal salvation.” Because to vote for a person who has expressed a fanatical determination to not only support abortion as it exists now but to remove all limitations on it through the Freedom of Choice Act, and to extend it without any recourse, throwing out all of the efforts of citizens over the last 35 years to place reasonable limits on abortion, that voting for a person who has expressed his determination to do this to Planned Parenthood, to NARAL — that you make yourself a participant in the act of abortion. That’s gravely wrong, and you mustn’t do it because your eternal salvation is tied up in that important choice.

You can listen to the rest of the interview here.
When blogged about this recently, the commenters were appalled that the church thought it could tell it’s members how to vote but the commenters obviously don’t understand that the church has the final authority on what the members are to believe, that issue was at the heart of the Reformation. The Catholic church has the final authority over issues of salvation and has come out quite strongly on this issue:

From its conception, the child has the right to life. Direct abortion, that is, abortion willed as an end or as a means, is a “criminal” practice (GS 27 § 3), gravely contrary to the moral law. The Church imposes the canonical penalty of excommunication for this crime against human life.

Morrissey notes:

Finn warns against formal participation in abortion, this time by enabling the government to dismantle the meager restrictions in place in some states to limit abortion on demand. The term “participant” is no accident; a participant in abortion becomes excommunicated latae sententiae,” “by the very commission of the offense.”

Catholics may do as they wish but if they really believe what they claim to believe, then clearly they are obligated to heed the teaching of the church otherwise they might as well be Protestants 🙂 The mainline Protestant churches would encourage your vote for a pro-choice candidate.