Some realism here. You have to measure debt as a percentage of GDP to have a good perspective.
This is the chart of US govt dept as a percentage of economic production (GDP):
The loans have such low interest rates right now (close to 0%) that this high debt is costing hardly anything.
Japan has around 200% debt to GDP - there we are talking real problems.
According to my schooling, anytime dept is over 100% to GDP trouble is baked into the cake