Thanks to Google Ngrams, which tracks the frequency of word use in all books in the Google Books corpus, political terms are traceable throughout the ages.
Putting aside any skepticism about Google's ability to catalogue every word used in history, the graphs do show us that some of these terms were popular in American English books as far back as America's early days, when national debt was a matter of debate for Alexander Hamilton and Thomas Jefferson, rather than Barack Obama and John Boehner.
Uses of "national debt," for instance, peaked in the 1790s, when Congress created the first national bank of the U.S. and when America still carried a national debt from the Revolutionary War. Uses of "austerity" peaked around the same time. "Debt Limit," meanwhile, peaked around 1920. Congress created the statutory federal debt limit with the Second Liberty Bond Act of 1917.