The national debt is about to hit $20 trillion (and a debt ceiling along with it). The US has not paid a penny on its debt in decades and shows no ability to do so anytime soon. Moreover, the US is issuing new debt to cover interest payments on the old debt.
The reality is that the US will never pay this debt down to an appreciable amount. Since the US prints its own currency it has several alternatives all with risk.
First, just keeping issuing debt and "encourage" the Federal Reserve to never normalize interest rates. Right now the annual budget is around $2.5 trillion of which about half is covered by issuing debt. Just keep adding a $1 trillion plus each year to the debt. If investors stop buying the debt have the Federal Reserve buy the debt by having the Treasury digitize the money and hand it over to the Federal Reserve. Since the US is the world's reserve currency this option would work until other countries began to dump the dollar.
Second, simply forgo issuing treasuries and have the Treasury Department create money in which to plug all gaps. There would be no interest because debt would not be issued. Again, this works until the dollar collapses.
Third, force a massive 75% write down in the debt to bring it to a manageable level. Investors would take a severe haircut. However, this would likely impact our ability to issue debt at low interest rates in the future.
Whatever way we go each option poses significant risk. Flood the country with dollars and we begin to look like Germany 1920s. Monetize the debt through the Federal Reserve or simply digitize money out of thin air to pay for budget shortfalls and the dollar risks a total collapse on the world stage.
However, any belief that the US will ever pay down a penny of debt is just a fantasy. Finally, with real productive economic growth barely moving hoping or planning for inflation will not happen. Forced inflation could occur in the event the dollar falls significantly but that scenario would bring on an entire different set of problems.