One scenario: Chief Justice Scalia?

Of all the possible candidates mentioned for a US Supreme Court post, none seems more primed for all-out warfare in the Senate confirmation process than Antonin Scalia.
Justice Scalia, who has served on the high court since 1986, is frequently mentioned as a potential nominee for the top post should Chief Justice William Rehnquist announce his retirement.

While the looming Senate showdown over filibusters is now focused on appeals-court candidates, such battles are considered mere window dressing for the ultimate prize - the future direction of the Supreme Court.

A Bush nomination of Scalia as chief justice would throw down a White House gauntlet to liberal advocacy groups. It would reassure religious conservatives that their support of President Bush in the 2004 election was not unappreciated. And, if confirmed, it would lay the groundwork to continue a nearly 40-year rightward shift at the high court by replacing a conservative chief justice with an even more conservative chief.

Details here from The Christian Science Monitor.