Abortion
Obama supports the Roe v. Wade decision that legalized abortion. He opposed the Supreme Court decision that upheld ban on partial-birth abortions.
McCain has long opposed abortion except in the case of rape, incest or to save the life of the mother. He calls Roe v. Wade “a flawed decision that must be overturned” so that individual states can set their own policies on abortion. “The difficult issue of abortion should not be decided by judicial fiat.”
When he sought the Republican presidential nomination in 1999, however, McCain said he opposed the reversal of Roe v. Wade because it would result in “thousands of young American women would be performing illegal and dangerous operations.”
Sources:
McCain campaign
Obama campaign
New York Times