Is deficit spending sustainable?

Are there any nations, except very small ones without their own currency, which take up loans in other currencies than of its own? Although some times private individuals of a country will speculate in taking up loans in the currency of another country. One thing that makes the US debt worse than the debt of many other debtor nations, like Japan and Germany, is that the debt is coupled with trade deficit. Supposedly meaning that a lot of the debt is now held by non-US citizens, so that not only will the repayment be money send out of the country, so will the hundreds of billions of dollars of annual interest. Money I’m sure could have been well-used inside the USA for schools, infrastructure projects, etc.

Some reading for anybody worrying about debt levels:

http://krugman.blogs.nytimes.com/2009/08/28/the-burden-of-debt/

http://krugman.blogs.nytimes.com/2011/05/24/debt-arithmetic-wonkish/

Quoth Derek Potter:

So let’s make sure we have a prospect of future income, maybe via tax rates like those of Reagan or Eisenhower.