Military and the Economy
Half of the American budget is devoted to defense spending and the economy would be in a real quandary without it. American political leaders would have to decide how to spend all the money freed up and since they believe in minimal government (except for defense, of course), they will face a real challenge. Possibly they could invest more in space travel to speed up our Mars program. Imagine the thrill of the average American, hungry or not, of witnessing such a stupendous technological accomplishment. If we are sufficiently fortuitous, we might encounter hostile aliens who would force us to spend more on defense again.
They could implement tax breaks for the rich but since they pay so little already, there would still be too much money remaining waiting to be spent. They could use the surplus after the tax breaks to further subsidize large corporations but then we might end up paying all their costs which sort of makes it a government program. Yikes
On the other hand, if the government has a problem in how to spend the money, they might turn to spending it on education, healthcare, infrastructure, and renewable forms of energy but it would be with great reluctance. It might be a real struggle for them since they are stealing profits from the private sector and that is not allowed in a free market economy. Maybe they could give a grant to the Chicago School of Economics for the purpose of revising their theories somewhat to accommodate this unexpected disaster (being forced to spend money on public programs and services). If there is a God, some group or nation will attack an American embassy or fire on an American ship so that the U.S. would be justified in taking over the world again.