Abortion
McCain: The senator has a strong pro-life record and supports overturning Roe v. Wade. He is in favor of federal restrictions limiting abortion, as well as a constitutional amendment banning most abortions, except in cases of rape, incest, or life-threatening risks to the mother. His selection of Alaska Gov. Sarah Palin, who is also strongly pro-life, has energized value voters who may have been uncertain about McCain's pro-life commitment.
Quote: "I will be a pro-life President and this presidency will have pro-life policies. That's my commitment to you."
McCain says he believes life begins at the moment of conception.
Obama: The senator is a staunch supporter of abortion rights. He supports Roe v. Wade and would seek Supreme Court nominees who would uphold that law. He also favors insurance coverage and government funding for abortions. He has advocated instead working to reduce abortions nationally.
Quote: "I am in favor, for example of limits on late term abortions if there is an exception for the mother's health. From the perspective of those who are pro-life, I think they would consider that inadequate. And I respect their views. What I can do is say there are ways we can work together to reduce the number of unwanted pregnancies, so that we actually are reducing the sense that women are seeking out abortions."
Obama has said he does not know when human life begins, saying that the answer to that is "above my pay grade."
Homosexual Issues
McCain: The senator opposes gay marriage but has also opposed a federal constitutional ban on them, unless courts begin to legalize the practice. He believes the issue should be left to states to decide. He endorsed an Arizona ballot initiative defining marriage as between a man and a woman. He supported the 1996 Defense of Marriage Act.
Quote: "I strongly support preserving unique states of marriage between man and woman. And I'm a federalist. I believe that states should make those decisions.If a federal court decided that my state of Arizona had to observe what the state of Massachusetts decided, then I would favor a Constitutional amendment. Until then, I believe the state should make the decisions within their own states."
McCain has held conflicting positions on civil unions.
Obama: Obama does not support a federal constitutional amendment on marriage, arguing that there is no historical precedent for defining marriage in the Constitution. He supports civil unions and says he would defer to the states to define marriage. He favors a full repeal of the Defense of Marriage Act.
Quote: "It's been a matter of state law that has been our tradition… the reason that people think there needs to be a constitutional amendment…is because of the concern about same-sex marriage. I am not somebody who promotes same-sex marriage, but I do believe in civil unions."
He says he personally believes marriage is between a man and a woman.
STEM CELL RESEARCH
McCain: He strongly supports federal funding for research, as long as cells aren't created for the sole purpose of destroying them. He has supported bills for more funding for adult stem cell research, a ban on the creation of embryos for research, and funding for research on existing embryos already slated for destruction by fertility clinics.
Quote: "I've come down on the side of stem cell research, but I am wildly optimistic that skin cell research, which is coming more and more into focus and practicability, will make this debate an acadmic one."
McCain opposes human cloning, or any related experimentation.
Obama: He favors relaxing federal restrictions on research. He voted for the Stem Cell Research Enhancement Acto of 2005, vetoed by President Bush. He does not believe embryos should be designed for the sole purpose of research, but argues that it is morally acceptable to use embryonic cells to find cures for debilitating diseases.
Quote: "I think that is a legitimate, moral approach to take. If we are going to discard those embryos and we know there is potential research that can lead to curing debilitating diseases. If that possibility presents itself, then I think we should, in a careful way, go ahead and pursue that research. In narrow circumstances, there is nothing inappropriate with us pursuing scientific research that could lead to cures so long as we're not designing embryos for that purpose."
He opposes human cloning.