A key Obama adviser has written a confidential memo in which he argues the U.S. should keep ~80,000 troops in Iraq until at least 2010. Obviously, that conflicts with Obama’s public claims of bringing troops home within 16 months of his inauguration.

The paper, obtained by The New York Sun, was written by Colin Kahl for the center-left Center for a New American Security. In “Stay on Success: A Policy of Conditional Engagement,” Mr. Kahl writes that through negotiations with the Iraqi government “the U.S. should aim to transition to a sustainable over-watch posture (of perhaps 60,000–80,000 forces) by the end of 2010 (although the specific timelines should be the byproduct of negotiations and conditions on the ground).”

Mr. Kahl is the day-to-day coordinator of the Obama campaign’s working group on Iraq. A shorter and less detailed version of this paper appeared on the center’s Web site as a policy brief.

Both Mr. Kahl and a senior Obama campaign adviser reached yesterday said the paper does not represent the campaign’s Iraq position. Nonetheless, the paper could provide clues as to the ultimate size of the residual American force the candidate has said would remain in Iraq after the withdrawal of combat brigades. The campaign has not publicly discussed the size of such a force in the past.

Obama’s own adviser on Iraq says the U.S. should sustain tens of thousands of troops in Iraq for at least another two years, yet Obama continues insisting on a surrender ASAP. The American population continues to come around to supporting a longer-term presence in Iraq.  Who exactly is he listening to, then?