If the US just washes their hands and leaves the war to Israel, we know what Israel will do and that is try to Gaza all of Iran. Iran will be forced to go full scorched earth on the Strait and oil and gas infrastructure anywhere they can reach it, in what will be a final war for Iran. One that will drag out similar to how Ukraine has neared final war stages with Russia and you just dig deeper.
We already see chaos due to gas shortages hitting certain countries (Irish army policing gas riots, etc) and soon that will result in a price shock increase for gas EVERYWHERE, including the US.
Trump said 'we get rich in America when gas prices shoot up' but the 'we' he meant was the US oil and gas companies and their shareholders. The average citizens of the US will get devastated.