The cost to the US to service its debt in 2015 was $220 billion, its GDP in the same year was 16 trillion.  I have a hard time believing that what accounts for only 1.3% of the productive output of the US is the number one determanent of its economic well-being, especially when 65% of that money goes right back into the US economy (i.e. interest on domestic debt).<p>Perhaps more than basic financial math is required to understand the economy?