I'm not predicting he would. But with Bush's spinal infusion, Scalia would see several like-minded justices on the court (Roberts, Alito, Thomas, and his own replacement). He's in his late 60s, and his "battle has been won." Why risk having to step down during a Democratic presidency?
Of course, he could stick around and enjoy the fruits of his labors, too.
I could also see Kennedy stepping down. He's too liberal for our liking, but I'm sure he's not so liberal as to want a Democrat to replace him. He did concurr with the 5-person authoritative decision in Bush v. Gore. He's certainly physically up to the task, but he is several years past Social Security retirement age.
If Kennedy stpped down, and was replaced by a solid conservative, it would also do much to dispirit Ginsberg and Stevens who seem to fighting for dear life to survive until a Democrat comes along, so they can preserve Roe.
Too many suppositions...lol.
Stevens should be the next to go. I hope it's before '08 elections.
Age is a better reason to stay than to leave, unless one is incapacitated by ill health. The late William Rehnquist suffered from cancer, yet was able to carry out his duties. And he did so quite well.