> tiny coalition of Israel and the US

This coalition is "tiny" insofar NATO & the GCC (well, apart from Bahrain and the UAE) refused to join the attacks, despite Iran's transgressions. The US could wage this war for many years all alone, and force the GCC to watch as the region burned. I guess, Trump's administration isn't willing to go as far as the current Israeli leadership may have hoped or wanted. That said, the war could very well still flare up, if the events from past 2 years following "talks" are any indicator.

Building coalitions is slow, deliberative work. Not a skills match for this administration, whatever your assessment of their overall aptitude is.