Certainly that's a good question, but you know the answer that derails it. what's in it for us isn't an operating consideration.
what's in it for Trump still demonstrates the self-destructive, self-contradictory nature of his mind. He's frustrated now about both the Russia investigation and the ancillary developments with the Cohen tapes. So flaming at Iran is his safety valve for blowing off steam.
Unfortunately, it's not safe. There is no safety. This evening, Lawrence O'Donnell asserted that Trump is all full of bluster and never follows through. He says that Trump has proven not to be a homicidal maniac willing to kill millions in his own orgy of reckoning.
But O'Donnell doesn't know that to any dead certainty. It's all very uncertain. Uncertainty is risk, and a lot of people -- some with health problems -- have to suffer through this endless stream of anxiety.
Oh -- almost forgot. Trump will do his best to upend the agreement with Iran for a totally unrelated reason: Obama was black; everything Obama did is wrong; and Trump must erase the Obama legacy.
How much of a legacy would you want to leave in place, on the other hand, if it's the legacy of an arch-traitor?