A heck of a way to bracket Obama's visit, uh, overseas, no?

First, Gen. Petraeus tells NBC's Andrea Mitchell that a withdrawal timeline ought to depend on "conditions," and specifically:

"...on missions set, depends on the enemy. The enemy does get a vote and is sometimes an independent variable. Lots of different factors I think that would be tied up in that. The dialogue on that and the amount of risk, because it eventually comes down to how much risk various options entail

That Petraeus granted an interview at this moment in time is not a coincidence.

Then, President Bush and Prime Minister Nuri Al-Maliki announce that they've agreed that "time horizons" are an appropriate way to begin to talk about withdrawing U.S. combat troops from Iraq. No such "horizons" have been set, and, of course, the administration is going out of its way to try and distinguish an horizon from a "timetable," but what we're really talking about here is a degree of flexibility and proximity. A horizon can be seen but it is often chimerical and it is a ways in the distance.

McCain tried to jump on the news proactively, citing "progress" as the reason for the announcement and projecting ahead to a time -- a horizon? -- when a "conditions-based withdrawal" is possible.

"When we withdraw, we will withdraw with honor and victory. An honorable and victorious withdrawal would not be possible if Senator Obama's views had prevailed. An artificial timetable based on political expediency would have led to disaster and could still turn success into defeat. If we had followed Senator Obama's policy, Iraq would have descended into chaos, American casualties would be far higher, and the region would be destabilized."

What's the difference between a time horizon -- which obviously involves the temporal dimension -- and a schedule? The degree of rigidity. But the directional push is clear: everyone is now talking about bringing troops home...Obama is most closely associated with the idea of bringing troops home... even as it may well be true that the reason why everyone's aboard the withdrawal wagon is because McCain championed the troop surge in the first place.