I think the Roman empire and the british empire both continued to fight wars right up until their empires collapsed. In fact the closer it got to collapse, the more of government activity that became devoted to war-making activities. War plundering is profitable. So it's always seen as "the way out" of the debt and decline that became endemic to those empires.

I think the US is undergoing something similar, but it will probably be even faster when it eventually collapses. Like the USSR collapsed overnight basically in 1991