On a broader historical timeline, US debt to GDP ratios aren't far from post World War II levels. We've been here before with disaster being averted. Good decision making and policies could reduce debt over a course of decades as occurred post WWII.
In the present scenario, its mostly about who has the most factories and the most consumption in a global market. Several countries have emerged as alternatives to the US. China being the most prominent. Already, investors are banking on a Chinese resurgence and investments are flowing into China. The shitshow in USA in terms of sheer divisiveness, stupidity and Trumpism is a pale marker of its former glory. If the debt condition was to worsen, I wouldn't bank on the US economy to show a miracle turnaround.