My short answer is that if Catholics have an informed conscience, they should feel free to ignore the immoral instructions from members of the Church hierarchy that make opposition to abortion rights the litmus test for supporting a candidate - but who at the same time ignore the issue of the prosecution of an unjust and immoral war.
There is a controversy that Catholics in American politics face - the fact that the Church hierarchy insists on mandating that their personal beliefs as Catholics must guide their work as legislators, government executives or judges (at least on the abortion issue).
Catholic public officials in a society ostensibly based on the principles of freedom and individual liberty, who may well as a matter of their own "moral" belief would not make a choice themselves to have an abortion, but who see a difference between their own personal beliefs as Catholics and the imposition of those beliefs on others who do not believe in the same way, are in trouble with the Catholic Church hierarchy.
For just one example of the directives that go out from the Vatican to constrain Catholic public officials in America, take a look at the following 2003 document published by the Vatican and issued by the Congregation for the Doctrine of the Faith (a Catholic Congregation in the Curia formerly known as The Holy Office and earlier, The Inquisition):
In this document, the Roman Catholic Church hierarchy actually states:
"When legislation in favour of the recognition of homosexual unions is proposed for the first time in a legislative assembly, the Catholic law-maker has a moral duty to express his opposition clearly and publicly and to vote against it. To vote in favour of a law so harmful to the common good is gravely immoral."
There are conservative Catholic bishops in America who have denied access to the sacraments to Catholic politicians who don't vote as the Church requires, when it comes to abortion or gay rights.
Vice Presidential candidate Joe Biden, a practicing Catholic, has been denied Holy Communion in the Diocese of Scranton, because the local bishop, like the people behind that dreadful document on marriage, is trying to meddle in American politics. (Sadly, the hierarchy doesn't do the same to Catholic politicians who vote for unjust wars.)
There is apparently an inherent conflict between the philosophy of tolerance and respect for disparate religious viewpoints that marks the American Experiment in establishing a democratic republic that has protection of individual rights, differences and dignity, and the repressive attitude of the Roman Catholic hierarchy, which wants to impose its version of Catholic morality on the secular world.
In my view, the Church oversteps its bounds. The private moral decision as to whether to have an abortion should belong to a woman. If she is a Catholic, she absolutely should take into account her beliefs as a Catholic as to the sinfulness of the decision. In America, people should have the right to make their own moral choices as long as no other living person is harmed.
While the Church considers all the rights of personhood to commence with conception, that actually doesn't have a great deal of support in sacred scripture (a much more likely time for "soul infusion" would be when a born person takes their first breath - but I shouldn't be arguing theology here).
There is certainly room for people of good will and different faiths to disagree.It's a similar thing with marriage - the Catholic Church doesn't have to sanctify a marriage involving a same-sex couple. If the Church wants to excommunicate gay Catholics who get civilly married, that is the Church's right.
But to tell Catholic politicians that even if they are never going to enter into a gay marriage themselves, that they must oppose civil marriage rights for gay people or be in a state of sin, goes against the principles under which the United States was founded.
Catholics in American public life are thus faced with a dilemma - if they obey the Church, they accept the anti-American idea that the Church position on a controversial issue is not only for Catholics, but must be imposed on everyone. If they don't, they can be denied access to the Sacraments, and be judged public sinners.
The Church hierarchy's position on this is untenable. Essentially, the only moral choice for a Catholic who respects the hierarchy's teaching and the underlying principles of American liberty and civil rights is to stay out of politics.
The moral depravity (yes, moral depravity!) of Church leaders who use their clout to try to force Catholics in politics to vote against their own consciences and the principles of American democracy and the liberties and freedoms we cherish - especially when it is on two issues and ignores a myriad of other issues, is despicable.
If a politician were to introduce legislation that would force women to have abortions, the Church would be right to be against it. If a politician were to propose that would force all churches to bless gay unions, the Church should rightly oppose it. These would be laws that interfere with personal moral choices that do not harm other people. (Fetuses may be "human life" but they are not (yet) people.)
But when Church leaders don't use their moral suasion to oppose an unjust war such as the invasion and occupation of Iraq, when they ally themselves with those whose political philosophy lacks true compassion for the poor and downtrodden, but instead rail against gay rights and women's rights. they show the true extent of their erroneous thinking.
Their meddling in American politics could hurt Catholics in American politics, too. it was not so long ago that Catholics were viewed with nearly the same sort of suspicion that many modern Americans see in Muslims today - Catholics were different; they didn't eat meat on Friday; their religious rites were in a foreign language; they were different from the WASPs who ran the country and were the majority.
In 1960, John F. Kennedy had to tell people that he would not be taking his marching orders from the Vatican.
In 1960, the Catholic Church wasn't giving orders to Catholics in public office. In 2003, they did.
If it wasn't for the fact that many Catholics in politics have used their consciences to try to separate Church teaching from the good of the American people, we'd be in a lot more trouble in this country than we already are.
What might work in a country where Roman Catholicism is the official state religion and all the people in the society must belong to the Church (or else) fails terribly in a nation built on principles that include religious freedom and individual human rights.
The Roman Catholic Church hierarchy oversteps its bounds when it interferes with the individual liberties guaranteed to all Americans.
So to my Catholic friends, use your moral compass and informed conscience and please vote for Obama on November 4th - he may not be perfect but he's a lot better than the other major candidate.