The US owes some $300 million in “military reimbursements” for Pakistan under he Coalition Support Fund deal, in which the Pentagon agrees to reimburse certain nations for costs incurred supporting US wars. Pakistan is normally a large recipient, because of the protracted US occupation in Afghanistan.
They’re not going to be seeing that $300 million any time soon, according to the Pentagon, however, because Congress recently moved to condition all funds to Pakistan on the Secretary of Defense certifying that Pakistan is taking military action against the Haqqani Network.
That’s not to say that Pakistan isn’t doing so, rather Secretary Ash Carter simply doesn’t seem to intend to certify it one way or another any time soon, and because of that, the Pentagon can get away with just not paying the money they owe to Pakistan.
Pentagon officials did, however, praise “the significance of the sacrifices that the Pakistani military has undertaken” to help the US war effort. That appreciation appears to fall well short of actually reimbursing them as promised, however.
This is so typical of the US. There exists only one treaty that the US has ever signed that it has not broken and that is the Antarctic Treaty. Why? look it up.