I was recently looking at the Israeli bombing of the Iraq nuclear reactor that was part of Saddam Hussein's nuclear program, that eliminated an Iraq nuclear capability in June 1981:

https://en.wikipedia.org/wiki/Operation_Opera

A reminder that things could be a lot worse right now, if not for the decisive action of the Israelis. A week or so ago, I saw a documentary, i9nterviewing a U.S. military officer, that the $3 billion a year we give to Israel pays for itself many times over. And this is certainly an example.

Likewise, I'm still convinced that for whatever errors assessing Iraq's nuclear threat before the 2003 Iraq war, Quaddafi in Libya saw the U.S. invasion of Iraq as a firm stance against nuclear proliferation, and turned over his nuclear program to U.N. inspectors for dismantlement. A nuclear program that no one even knew he had!

So I think that alone justifies the Iraq war.
Despite Obama's fucking it up with a complete Iraq withdrawal in Dec 2011, that destabilized the region, caused the rise of ISIS, and almost lost the gains made there. If not for the decisive action of Trump in 2017-2018 that reversed Obama's losses. But regardless, because of these actions, nukes have not proliferated across the Middle East. North Korea and Iran still remain a potential threat in the wings, though. At least we have the right president for the job on these as well.