Every year the U.S. Government collects revenue from taxes and spends it on its public programs and agencies. Every year it irresponsibly and unconstitutionally spends (largely wastes) more than it earns, so that its yearly budget results in a deficit.

To cover the deficit, the U.S. Treasury borrows money (by selling securities like Treasury bills, notes, bonds and savings bonds to the public), just like an individual who spends more than what he earns has to borrow the missing amount from a credit card.

The accumulated deficits year after year form the outstanding U.S. national debt which is astronomical and rising at warp speed.