A word on timing: it won't be this week. It won't be early next week. It probably won't be late next week. Most likely: the week after Memorial Day, when Obama is in town, and free -- he's traveling or meeting foreign leaders through Friday, the 29th. Members of Congress will be out of town; that makes it easier to direct the message, makes it tougher for Republicans to come up with a unified response, but also prevents Congressional Democrats from becoming validators.
If you put a gun to my head and asked me who I really thought was on the short list, I would swear to you that I don't know, and I would profess my fear that Howie Kurtz would call me out if I named names. On the other hand, if you applied Ali Soufan's interrogation techniques to me, I would probably say that Sotomayor, Woods, Kagan and Moreno were some of the names on that list.
One of the interesting dynamics to watch: the White House doesn't want interest groups to make the case for particular nominees. Why? Because the White House doesn't want to appear to be responding to any interest group pressure when they make the announcement. That's why the pre-decision period has been relatively quiet on the organized left.
.... The President has gone to his trusted circle (and those who can be vouched for from his trusted circle) whenever he can for sensitive positions. This explains Valerie Jarrett, Cass Sunstein, and others. When he's gone outside his circle, as with the choice of Vice President Biden, there's greater room for tension and mismatch. Judge Wood comes from the same University of Chicago circles, and she can be vouched for. She would not be a "stealth" Justice, as Justice Souter was.
3. Nominating Judge Woods gets a progressive judge on the Court using the Roberts/Alito playbook. If you choose someone who has a truly excellent reputation as a judge, it becomes very hard for opponents of that person to block the nomination on ideological grounds. If the real goal is getting a progressive leader on the Court, this is the easiest path.
4. The other nominees present harder paths to nomination. There have been attacks on Judge Sotomayor's temperament and ability to work with other judges. My colleague Rob Kar has responded to these attacks, and vouches for the judge's intelligence and temperament. But it will be a battle, and one that would be fought over whether the judge, whom opponents will say would have been chosen for her ethnicity, is an outstanding judge. (See Eric Posner's evaluation of Judge Sotomayor's appellate record using Gulati and Choi's framework, concluding the judge is about average, or slightly below average, on a number of measures.) President Obama could have this fight, and probably win it, but the question is whether he wants to spend his political capital on this when he is fighting over health care, the economy, the environment, and so many other things in Congress right now. A Roberts-like hearing moves quickly, and gets the country back to other business.