McCain is likely a good fit for pro-choice Democrats

Hillary Clinton's blessing notwithstanding, many of the New York senator's supporters will resist the handover to Barack Obama. The sexism that permeated the recent campaign still rankles, and John McCain is far from the standard-issue Republican they instinctively vote against.
A big sticking point for wavering Democrats will be McCain's position on reproductive rights. Clinton's backers are overwhelmingly pro-choice, and they'll want to know this: Would McCain stock the Supreme Court with foes of Roe v. Wade? The 1973 decision guarantees a right to abortion.
The answer is unclear but probably "no." While McCain has positioned himself as "pro-life" during this campaign, his statements over the years show considerable latitude on the issue.
In a 1999 interview with the San Francisco Chronicle editorial board, McCain said, "I would not support repeal of Roe v. Wade, which would then force X number of women in America" to undergo "illegal and dangerous operations."

http://www.chron.com/disp/story.mpl/editorial/outlook/5832027.html