The only question is how will India respond, for India cannot let this go without a response. And I, for one, would not expect India not to respond.
And what will the US do if India goes after Pakistan? What will Pakistan do?
If India ever goes after Pakistan in earnest, Pakistan will lose. I have no idea how the US will react, other than the State Department will condemn any action. This is what the State Department does. As for the remainder of those in D.C., the democrats will cry foul and demand India quit kicking Pakistan’s butts. Republican will probably remain quiet. But I do not expect anything other than an investigation and assorted arrests, coupled with a ‘back channel’ warning to Pakistan, if those who did this turn out to be from Pakistan.
Offer Musharraf a secret slot in the Witness Protection Program, then pass the popcorn.