The Man Who Sells America’s I.O.U.’s
nytimes.com
nytimes.com
Your best hope is that by the time your bond matures someone else will "invest" to cover you but what happens if they finally reach a point where they can't borrow enough to pay their existing obligations?
Regarding your second point, the situation isn't hopeless. The graph with the article shows that it is possible to reduce the national debt, both in real terms and as a percentage of GDP.