Given the response from a large segment of Trump's base, if the U.S attacks Iran, I am skeptical there will be a United States at the end of this decade.
Everything is stretched too thin as it is and the polity has been meta-stable since 9/11 and the Great Recession.
Another war like this likely leads to the end of the United States. The only Americans who want this are a majority of Christian Nationalists and the Neo-Cons. And while they are large groups they're only, generously, a fourth of the population.
This could lead to a French Revolution/Russian Revolution event in the U.S, in my opinion.







