I think this will be a regional war. For once, all the main actors in Iraq have already given their final, final warnings for US illegal troops to leave and saying that they would attack full force if the US attacked Yemen, already started attacking again tonight. There will probably be escalations in Syria too, Hezbollah will put more pressure on Israel, so the US will effectively have to fight all of them at the same time, and that is without Iran (which will provide material support 100%). The US can either commit to sending more resources everywhere or lose on some fronts. Shipping costs will go even higher, the oil prices will go up, and there will be more inflation in the US that wouldn't have been there without the US stupidly escalating the situation even further. And all that in an election year. The US politicians are so stupid nowadays that they can't even do good for their own campaigns, how do you expect them do to for the entire country then?