FWIW, among actual Roman Catholic thinkers, it is considered right to vote in such a way as to best restrain evil. It would require more than “this guy stinks” to disqualify a vote for him as a reasonable means to that goal.
A Catholic cannot vote for either without incurring excommunication latae sententiae (automatic) for materially cooperating with abortion. I am a Catholic. IIRC, with all due respect, you are not. I cannot very well purport to speak for those of other faiths and I do not. It is up to those who adhere to such other faiths to speak and decide for themselves. OTOH, I am not likely to take instruction in Catholic morality from non-Catholics either. I'll rely on the Teaching Magisterium, the Catechism of the Catholic Church, Canon Law and similar sources.
Some may call the despicable likes of Fr. Charles Curran, the late Fr. Robert Drinan, SJ, the apostate former nun Frances Kissling of "'Catholics' for a Free Choice" and others of their ilk "Catholic" in the sense that they were once baptized Catholic and "thinkers" in the sense that, despite appearances, they have or had functioning brain cells at some point in life. What they were not was actually Catholic. What they are or were is or was self-excommunicated servants of Satan. Neither Obozo nor Romney were themselves excommunicated from the Catholic Church because neither was ever Catholic in the first place.
That does not mean that actual Catholics can take out the old political scales and see which of these despicable excuses for humanity puts a smidgeon more weight on the scale. Evil is evil. Voting for evil makes one evil. Rationalizing will not save one's soul.
The moral relativism espoused by you and other Romney pom pom girls (without regard for Mittler's career of support for mass baby-killing, Church persecution and "gay" everything) may be many things but CATHOLIC is not one of them any more than the sorry souls (like many in Catholic Worker or who are otherwise enslaved by the Demonrat Party) who rationalize for Obozo because he wants to advance socialism and other evils even more quickly than Mittler without regard for his mass baby-killing, Church persecution and support for "gay" everything, have any business calling themselves "Catholic."
There is absolutely NOTHING in the history of Mittler or Obozo that would suggest that either of them would EVER act in such a way as to restrain evil. For either of them that would suggest self-restraint (fat chance of THAT ever happening) since both are EVIL. They both "stink" and both are disqualified for the votes of any rational person who wants to achieve other than evil. This is black and white morally and not the sort of prudential judgment that results from an analysis of alleged shades of grey.
If credible post-election polls were to show that no Catholic voter voted for Obozo and no Catholic voter voted for Mittler, then you may rest assured that the GOP, at least, would never nominate another evil candidate such as Mittler. Regardless of the volume of self-serving lies told by future Mittlers, regardless of the mountains of corrupt money used by future Mittlers to buy GOP nominations, regardless of mass hallucination that anything vaguely resembling either Mittler or Obozo could EVER be other than evil in office.