Why did the Cockatoo-in-Chief renege on Iran deal deeply prized by Russia, China, France, Germany, England, and the European Union? Why did he deliberately damage relations with Europe and cost American workers many thousands of jobs at Boeing among others? Why do all of this to hurt a country that poses no danger to the United States?
Israel, Israel. Israel. Israel.
If Iran were a threat to the existence of Israel, things would be different. If Muslims conquered the Jews, they would presumably treat them as badly as Israelis, and very likely worse. It would be ugly in the extreme. To prevent this, use of the American military would be justified.
But Iran does not threaten the existence of Israel. It does threaten Israel's dominance in the Mid-East. Iran is far larger and more populous than Israel, strategically located, and has vast amounts of oil. It is a large market for many European products. By contrast, Israel is small and has nothing anyone needs or wants. Left to itself, Iran would become the dominant regional power. It moves fast in that direction now with burgeoning trade with Europe in, among many other things, airliners. With economic influence comes political influence.
Consequently, Israel does not want Iran to prosper. If it can, Israel will use the American military to prevent this prospering. It will destroy America's relations with the rest of the world to prevent it. It is doing so.
As thinking people know, the twaddle about the Iranian's development of an atomic bomb is just that–twaddle. The Europeans know this, which is why they are not alarmed. The US government know it, since the intelligence agencies have repeatedly said that Iran does not have a program aimed at producing a nuclear weapon.
But: Whenever the American government, or those controlling it, wants to drive the US into a war, it invents a frightening danger and warns of it over and over and over until a poorly educated public believes it: The Maine, the Gulf of Tonkin, Iraq's WMD, the Iranian bomb. It's a frightening world, Washington tells us. Things go bump in the night. Boo.
Where does Trump fit into this? Although his supporters offer him as a masterly statesman, biographies, which few read, show him to be profoundly ignorant, incoherent, narcissistic, weak, and easily manipulated. He loves attention and craves praise. He is also corrupt. As a businessman he danced just this side of the law in many shady real-estate deals. All of this is documented, but few will read of it.
Some will say that this isn't true. Go back and look at the things he said during the campaign, the positions he was going to take before he was modified. He astonished people who worked in his White House not just by his lack of knowledge but his lack of interest in learning. We are ruled by a histrionic dwarf.
But, in a country with no checks and balances on presidential power, foreign policy is what he says it is, and America attacks whoever he wants it to attack.