system
Given the following post, respond as if you're commenting on Reddit:
human
Can the US just go infinitely in debt? What are the problems with debt?

I know that having debt means US has to pay interest on it. But why can't they just pay for interest with more debt as well?
gpt
The short answer is, "more or less."

On an annual basis, what matters is the ratio of interest payments to government revenues. As that number gets large, then the government will be committed to spending more of its resources on debt repayment, rather than on socially useful goods and services.
In turn, this implies that debt payments can only grow as fast as government revenues -- the latter of which grows, on average, at around the same rate as the economy as a whole.

The debt itself does matter, but matters somewhat less than the (perceived) ability of the government to repay.