Karzai is playing the U.S. - we've given him several warnings, but he continues to delay signing an agreement until Afghan's June(?) election so he can maintain power as long as possible. Time to stop warning and just make plans to leave, which I suspect is happening behind the scenes.
"...the empty desks of 20 children marked absent today, and forever"
-Poet Richard Blanco at President Obama's Inauguration, 01/21/13