From a game-theoretical perspective, the key question is whether Iran was actually developing a bomb with the intention to use it, rather than adhering to the Cold War logic of deterrence. Most people seem to assume the latter, but the former was also a plausible possibility.
There's no game theory to question. Israel has second-strike capabilities, and even if they get completely glassed America would retaliate by cratering Tehran. Iran needs a nuclear weapon for the precisely same reason Israel's state demands them; it's a credible last-ditch deterrent against invading forces. A strategic weapon when the chessboard is scrambled.
Whether or not any of that is justified is another question, arguably long since expired. Strategic arms reduction is a two-way road, it requires transparency and genuine humility from both parties at the table. It's why Reagan could never secure his deal from Gorbachev, and it's why Trump won't reach a deal playing "mad gunman" with the B-2.
