My guess is US debt will not be a major problem until it is, and then it will be a crisis(real one). As long as there is good demand for treasuries, should kick the can down the road. But sure would be nice to have that money to spend on something useful. Pretty crazy spending more on interest payments than national defense now:
21 % Social Security
14 % Medicare
13 % Net Interest
13 % Health
13 % National Defense