Personally I'm only concerned with my debt. National debt implies just one country but alas in the recent world economic crash it has shown just how much all countries are interlinked.
While it might be nice to think that your own countries government is standing solely for its people, it is not at all practical. No one government at present has the wealth or might to stand alone.
Their financial dealings are so interlinked, so entwined, that none of them can stand up and say "we are doing this for our people, to heck with the rest" before another would say "I don't think so, pal".
Just an opinion but I think "World Debt" has superceded any notion of "National Debt" ,