ohhh my favorite argument of all...Let's battle our National Debt! How about let's not. Us having a debt means that others have confidence in us, it also means that it is in their best interest that we do well. A debt at national level can not be called, so it's not like china for example could say "give us all you owe us or we'll enslave you all and take your lands".
It's just one of those propaganda words they use , and in this case both major parties use it, to make it sound like there isn't enough to go around, there is. They use it whenever it's time to decide over social security benefits, medicare etc to keep people peacefully quiet about cuts.