Let's have a look at the US economy.
In theory, growth is fairly decent, inflation appears to be ok, unemployment is alright, the deficit has shrunk a bit, happy days.
However, there are some major flashing red lights.
Fund’s forecasts suggest the country’s debt-to-GDP ratio will be at a record high by the end of the decade
www.ft.com
The US has run a budget deficit of about 7-8% of GDP for the past few years, the monthly figures are significantly reduced, Nov 25's deficit is a mere $193bn vs $367bn in Nov 24. Spending is down $160bn, but that's at least partly due to the shutdown, which will have significant longer term costs. Customs duties brought in $30bn extra.
Those are monthly figures though. They're still running about a $2.5 - 3 trillion annual deficit, between tax cuts and import tariff revenues, they kinda balance out, both making a $4tn impact both ways. The deficit is still pretty damned high and nothing the US government has done to date has really fixed it.
According to the IMF, debt to GDP is due to hit 125% of GDP this year and 143% of GDP by the end of the decade.
10 year treasury notes are pretty stable, nothing panicked at this point, however debt servicing costs are due to hit $1 trillion and as much of that turns over, that cost is only going to rise over coming years. Which makes the deficit much worse.
There are two major threats:
1. GDP growth slows
2. Confidence in the dollar drops
For #1, there's no doubt that AI is fuelling at least a decent chunk of US GDP growth. How much? That's disputed.
If the AI bubble pops, that will undoubtedly negatively impact GDP quite hard.
The fact that the Fed is planning to buy treasury bills now is not going to help #2, it's not a disaster but it's a bit odd and somewhat concerning. The sort of thing a Latin American country would traditionally do, right before their currency drops like a stone...