You do not win a war by bombing the clappers out of the country. By simply staying on their feet Iran wins the war and the USA and therefore Trump looks impotent.
As I said before if you wish to destroy the nuclear program, reduce its missile and drone capacity, have regime change and have it withdraw from financing various terrorist groups then you have to have boots on the ground. Even then the results would be problematic. There would be lots of well armed people willing to kill US soldiers. The politics is also against it. It is already a very unpopular war. This would make it more so. Why were they killed would be a devastating question.
Thus we we have trump and his incompetent defence secretary having overreached themselves. However it gets worse. Iran now have done so.
We live in uncertain times and i have no idea of how this mess gets solved.