Instead, McCain galvanized his support with conservative activists when he chose Alaska Gov. Sarah Palin, who opposes abortion even in cases of rape and incest.
McCain's website says he "believes Roe v. Wade is a flawed decision that must be overturned."
But having established his opposition to abortion, McCain has no reason to campaign on the issue, Khachigian said. "At this stage, when you focus on the 10% who are out there and have not decided, you can figure they are not going to decide based on your view of abortion or Roe vs. Wade," he said.
Democrat Barack Obama has called himself a strong supporter of abortion rights.
"A woman's ability to decide how many children to have and when, without interference from the government, is one of the most fundamental rights we possess," he told NARAL Pro-Choice America. "I believe we must work together to reduce the number of unintended pregnancies," he said.
But Obama, like McCain, does not talk up the issue on the campaign trail.
Polls show the American public remains closely split on abortion. Most say they favor legal abortion, with some restrictions. In August, a poll for the Pew Research Center for the People & the Press found that 54% said abortion should be generally legal, and 41% said it should be mostly illegal.
This week, the Supreme Court opens its term, and abortion is not on the docket there, either. The justices have generally steered away from abortion-related disputes in recent years. They remain closely and bitterly divided on the issue.
Four justices -- Ruth Bader Ginsburg, David H. Souter, Stephen G. Breyer and Stevens -- have consistently supported the right to abortion, and they have voted to strike down restrictions.
Justices Antonin Scalia and Clarence Thomas have said the Roe decision should be overturned, leaving the states or Congress to decide the abortion issue.
Chief Justice John G. Roberts Jr. and Alito served as young lawyers in the Reagan administration, which was committed to reversing Roe. And since joining the court, they voted to uphold the federal Partial-Birth Abortion Ban Act.
In the middle, Justice Anthony M. Kennedy has supported strict regulation of abortion, but he has opposed a ban.
If Stevens or Ginsburg were to be replaced by a staunch conservative, that would tip the majority against abortion rights. However, it is not certain that Roberts and Alito would join Scalia and Thomas in pressing to overrule the right entirely.
