Since the passage of Roe v. Wade, there have been eight Presidential elections of which the GOP has won five, or 62.5%. Supreme Court appointments have been even more lopsided, with the GOP appointing eight of the ten persons to go on the Court since Roe v. Wade was decided. Several are likely to retire during the next President's first term, but the GOP's edge in Presidential elections probably means that it will select more Justices over the next fifteen years even if it loses the 2008 election.
With the rise of members of the Federalist Society to prominence in the legal profession, the nomination by a Republican President of a "stealth liberal" in the mold of David Souter, or even an open moderate like Sandra O'Connor, is increasingly unlikely (witness the failure of the Harriet Myers nomination in 2005). The evangelical base of the Republican Party (as distinguished from country-club conservatives and conservative-leaning independents) has gotten more, not less, serious about abolishing legal abortion in the last decade and a half. It is entirely willing to become a permanent minority if it can achieve success (even temporarily) on its signature social issue.
Challenge Jason W Galbraith to a bet on this prediction!