The diaspora can play its role, but it needs an economically strong and prosperous Pakistan to really shift policy. Even with that, there will be little more than strong public statements. The Indian diaspora has significantly more clout than the Pakistani diaspora in the US, but has the US sanctioned Pakistan? Despite stacking the State Department with pro-India hawks, have the recommendations of people like Christine Fair, in terms of punitive actions against Pakistan, been implemented, despite Pakistan having significantly less economic clout than India or no utility vis a vis the US’s goal of ‘containing China’?
Of course Pakistan’s nuclear weapons erode the advantage of the Indian economy & Indian American influence, which gets back to my point that neither India nor Pakistan will be able to leverage the global community in any significant way against each other. India’s current advantages will be eroded with Pakistan’s economic progress and even the FATF restrictions are a silver lining in that much of the actions being pushed will also have a significant impact on black money/money laundering due to corruption, which in turn will help Pakistan’s economy & domestic security in the long run.
Most of the diaspora is looking for all their own well being. They better be looking out. In UK you had a few thousand protestors in London out of 1.2 million Pakistani/Kashmiri community. In USA 2nd and 3rd generation Indian/Pakistanis intermarry with others and could care less.
USA and India relationship is bound by economic interests. In the long run it is a much more lasting bond than nukes or Afghanistan. Pakistan has not prevented NSG waiver, NSG membership or other measures that USA has pushed for India. China stopped India's NSG membership for its own reasons. Ever wonder why American allies like Saudi Arabia and UAE are closer to India recently ?