If the United States continues on its current path of growing, unmanaged national debt, the country will eventually experience a serious national decline or crisis ("take us down" / "fold"), and U.S. political leaders will be forced into increasingly cowardly or poor decisions as a direct consequence of servicing that debt.
“the debt of the nation will take us down. We will fold because the debt we have, and it's going to be unmanaged debt, which will make us lead us to make cowardly decisions.”