There is a way to look at the Iran situation as America First
OPINION
There has been much back and forth as to whether Trump has violated his America First principles with the Iran conflict. I will not rehash the arguments. Rather I will point out a way in which it can be argued that the Iran conflict is in keeping with America First principles.
Consider the result of the conflict as it pertains to US interests. The main reason anyone in the rest of the world cares about the Iran conflict is the effect it has had on oil flows via the Straits of Hormuz. Having effectively taken control of Venezuelan oil production by removing Maduro, and then greatly reducing the flow of oil from the Middle East, Trump has created a situation where the US oil industry takes a major portion of market share away from the Middle East countries. Add to that the fact that recovery for the Middle East may well take a considerable amount of time, and US companies will likely be involved to a significant degree, and you have an outcome where a vital industry which had weathered significant hardships over the last few decades due to Climate Change agendas, now has room and sales to rebuild itself, both domestically and internationally, with all of the secondary effects which will result as well.
There is an additional effect as well. Most of China's oil is sourced, or was until recently, from the Middle East. With those flows throttled they have two options, reduce economic activity/growth or find a new supply, a demand which the US oil industry is increasingly well positioned to capitalize on which will in turn reduce the trade imbalance which has existed with them for so long. And the more they rely on us for their oil the less likely they are to engage in activity which might endanger that supply.