From the linked article:
“…In these circumstances, will the governments of countries that buy large quantities of U.S. bonds – China, the Gulf States and Russia, for example – be ready to continue supporting the dollar’s role as the world’s reserve currency? Or will these countries see this as an opportunity to tilt the balance of economic power further in their favour?”

If the US economy tanks catastrophically, all those foreign govts holding our debt, and invested in us, are just as screwed as we are. The smart people in those countries will do their damnedest to not let that happen. As long as we owe a lot, we have leverage. That’s the nice thing about allowing foreigners to invest in America- it’s in their interest that we succeed. And a side-effect of global economic inter-dependence is that we sink or swim together.