Why Did We Block Goldstone's Report?

Marc Lynch wants to know what the Obama administration was thinking:

There seems to be little question that Abbas's decision to go along with American pressure will have a significant impact on the popularity and legitimacy of the PA.  He is already backpedaling in the face of the intense public backlash, announcing the formation of a committee to look into the "circumstances surrounding the issue" (gee, wonder what he'll find when he investigates his own decision?), but it's probably too late.

[...]

I can understand the decision to sacrifice the Goldstone inquiry into the Gaza war to tactical or strategic considerations, whether or not I agree with the call.  It wouldn't be the first time.  But I would hope that such a decision would have seriously anticipated the implications for the legitimacy and efficacy of the Palestinian Authority, for Obama's credibility among Arab and Muslim audiences, or for how to leverage it into real gains with the Israeli public. 

It appears at times that Obama does not have the final say over US foreign policy in the Middle East. Israel does. At some point, it is not unreasonable to ask for a little help from our alleged friends.

(My first version of this sentence was intemperate and over-wrought. I apologize. My point is strong enough without stupid exaggerations.)