The impression of the Trump base is that he can fail all day long on the foreign stage and it will not matter one bit. Surely they'll hand-wave it away like any other bad (sorry "fake") news. But how high does foreign policy rank on the radar of the nationalist, protectionist, 'Merica-first Trump voter? They like him because he won't play with all those foreign loser types.
This is the guy who tanked the Paris Accords, backs out of trade deals, regularly denigrates the UN and NATO. If he does well with anything they'll say "Look what a deal-maker he is!" But if we end up in, say, a trade war with China it's because, "He's a tough negotiator and won't take any crap!" The myth of Trump as the mighty negotiator persists and explains all the successes and all the failures.
Trump understands that foreign crises or even war are the way to divert from domestic problems, so will keep war-monger Bolton around so he can egg Trump on. Other than Bolton, who are Trump's top foreign policy advisors? Kushner, Hannity and Putin? Any others? Stephen Miller?? Does Trump still look to Steve Bannon for guidance?
Kushner is way past his Peter Principle ceiling and, at best, can be trusted to relay the wishes of two MidEast tyrants: Netanyahu and MBS al-Saud. Hannity will say whatever will leave him in Trump's good graces.
This leaves Putin. Trump pretty much does Putin's bidding. Putin will deploy his asset carefully: he doesn't want the asset to become ineffective from excessive ridicule.
So..IMO (right now) war with Iran is a long shot. Trump drums up a war against Iran on even weaker reasons than the war against Iraq. That would be a big re-election mistake