Hagel's unannounced visit puts him in the center of the chaos. However, he may have little impact on the matter during his stop because he's not planning to meet with Karzai.
The US has made its position on the security agreement clear. And Karzai tentatively has endorsed the deal, but refuses to sign it.
Karzai says he wants his successor to decide on the agreement after the April 5 elections. Washington and NATO officials say they want a decision soon.