Timetable or Not?

Voters are split, again. Marc speculates why:

...my best guess is that partisan differences are reasserting themselves -- Republicans and Republican-leaning independents are coalescing around their nominee and his position. Or maybe this is a tribune to McCain's astonishing personal brand; or, the American people have moved on Iraq from 2006 and tend to accept the premise that The Surge is working.

Or maybe it's a tough call. And what Obama calls listening to the generals on the ground and what McCain calls leaving victoriously may end up being relatively similar when it comes to 2009. The difference the seems to me to be the salient one is long-term intent. Are we there to stay for ever, with the invasion regarded as a launching pad to confront Iran? Or do we intend to leave as soon as possible, because enmeshment in Mesopotamia for the next few decades will be much more trouble than it could possibly be worth?