The US isn't interested in a war, they are however interested in the Iranian proxy influence which has long threatened allies.
As of now at least 1 UK national is detained in Iran wrongfully accused of spying. A British ship was taken hostage last year and a ship we detained for going to Syria to sell illegal oil was released and then went to Syria to sell illegal oil......
The Saudi's were also bombed which halted half of their oil production and caused hundreds of millions of $ of damage.
Many are quick to condemn Trump but if you consider the history then few will mourn the death of Soleimani as they won't Al-Baghdadi.
We have to defend ourselves and we have to deter those who may seek to do us or our allies harm.