Hosting Karzai at the White House, Obama faces the challenge of pressing ahead with his re-election pledge to continue winding down the long war in Afghanistan while preparing the Afghan government to prevent a slide back into chaos and a Taliban resurgence once most NATO forces are gone.
Karzai’s visit, which follows a year of growing strains in U.S.-Afghan ties, comes amid stepped-up deliberations in Washington over the size and scope of the U.S. military role in Afghanistan once the NATO-led combat mission concludes at the end of next year.
White House officials have left open the possibility of a complete U.S. withdrawal after 2014 - as happened in Iraq in 2011 - an option that conflicts with the Pentagon's view that thousands of troops will be needed to bolster and train still-fragile Afghan security forces.
But talk of this “zero option” may actually be a gambit to squeeze concessions from Karzai, who has yet to agree on immunity from prosecution for any U.S. forces that stay behind under a bilateral security pact being negotiated. It could also send a message to the Pentagon to scale back expectations of future troop levels.
The White House believes Obama and Karzai, despite a history of sometimes tense relations, can narrow their differences. But Obama aides expect no breakthroughs or concrete agreements and say it will be months before Obama decides how many troops - if any - he wants to keep in Afghanistan.
U.S. officials have said privately that the White House is asking for options to be developed for keeping between 3,000 and 9,000 troops in the country. General John Allen, the top U.S. and NATO commander in Afghanistan, had initially suggested that as many as 15,000 troops should remain.
With some 66,000 U.S. troops currently in Afghanistan, Obama is also deciding on the pace of this year's troop reductions. Afghan forces are due to take the lead role in security across the country in 2013.