Debt is symptom not a underlying cause. As well big defense budget and very big valuations (1). This is according to Klain and Pettis diagnosis that I think is correct one or at least close to being correct (from the "Trade wars are class wars" book - do not worry this has nothing to do with socialism).

Basically they argue that US (and other trade deficit countries) and China (and other trade surplus countries) are creating mirror imbalances that would have to be rectified - either by policy actions or when driven up to conclusion by system breakage. Like Great Depression or Japan lost decade on the surplus side. And possibly inflationary crisis on deficit countries (but this is my interpretation - I do not think they claim that and I might have not understood something).

In that lenses latest political development in US does make more sense.

(1) trade deficit pushes assets price up - as dolar from trade surplus has to return to US somehow - to buy stocks for example. That would also explain why market looks so good even if "real economy" is not so hot - but as US trade deficit is big so is stock demand. Similarly trade deficit pushes unemployment up - to keep it in check federal policy has to intervene. Could be by Biden IRA or by Trump big defense spending. This in turn results in big budget deficits.