Notice the timing on these two bits of news. Pakistan takes pot shots at America, and America fires back.
A bit of brainstorming:
Based on this Q post, ARM could be an acronym for:
A group of black hats inside the House of Representatives - where R is Ryan
A group of black hats in Congress - where M is No Name
A group of black hats in US government - where R is Rosenstein and M is Mueller (however we don't know for sure they are black hats)
A composite group including British folks - where M is May