Anyone who has carried a balance on a credit card knows the part of debt that actually hurts.
It is not the number you owe
It is the rate attached to it. A $10,000 balance at 3% is a nuisance you manage. The same balance at 20% starts making decisions for you.
The federal government runs on that same arithmetic, with more zeros and fewer exits. Washington has spent the past several years borrowing the way a household leans on a low introductory rate, taking the cheap money now and assuming it stays cheap. For a while, the assumption held.