These are the states whose Senators are in play this year [1].
Let's say Trump decides it's fuck-around-with-Islamabad-o'clock. He fucks around. Pakistan nukes at India. How many of those Senate seats flip as a result? I'm going to guess none.
Let's go one step further. Pakistan nukes Al Udeid and Camp Arifjan (both theoretically within range of their Shaheen-III). American troops are killed. Does the President's party lose any seats? At that point, I'd bet on a rally-'round-the-flag effect.
The truth is there isn't political downside to the President fucking around with Pakistan. Its nuclear deterrent isn't designed to contain America. And it can't threaten us with maybe the one thing that could make Trump suffer, a refugee crisis.