Which of these debt peaks was unsustainable, and why?<p><a href="http:&#x2F;&#x2F;www.mybudget360.com&#x2F;wp-content&#x2F;uploads&#x2F;2010&#x2F;12&#x2F;us-public-debt-vs-gdp.png" rel="nofollow">http:&#x2F;&#x2F;www.mybudget360.com&#x2F;wp-content&#x2F;uploads&#x2F;2010&#x2F;12&#x2F;us-pub...</a>