AI companies compete with the US Treasury for capital, driving up interest rates the government can't afford. Simultaneously, AI aims to eliminate white-collar jobs that form the core of the federal tax base. This creates a "snake-eating-its-own-tail" dynamic that pushes the US closer to a fiscal crisis.

The CBO, the US government's nonpartisan budget forecaster, projects long-term productivity growth of only 1% annually. This baseline, which informs official deficit projections, is lower than the post-1995 average and assumes AI will not create an extraordinary productivity surge, positioning the CBO as pessimistic compared to tech optimists.

The AI industry and the US government both require trillions in funding. This creates a paradox: the more successful AI becomes, the more it erodes the white-collar tax base by automating jobs, forcing the Treasury to borrow even more and intensifying the competition for scarce capital.

The ability of Western governments to manage their enormous public debt levels is now implicitly dependent on the hope that AI will generate a massive, sustained productivity boom. If AI fails to deliver this unprecedented growth, a widespread fiscal crisis becomes a serious risk.

A significant, non-obvious downside of AI's impact is its potential to radically improve healthcare and extend lifespans. While great for humanity, this directly burdens the federal budget. Longer lives mean more years of drawing Social Security and Medicare benefits, significantly increasing the long-term unfunded liabilities of these entitlement programs.

Among the five factors eroding AI's positive fiscal impact, a projected 35% rise in interest rates is mathematically the most significant. With US debt already at 100% of GDP, even small changes in borrowing costs have an enormous effect on the deficit, overwhelming other factors like defense spending or labor force changes.

A simplistic view of AI replacing tasks is misleading. A more robust model treats the outcome as a race between three competing forces: the speed of AI diffusion versus labor rebalancing, task destruction versus new task creation, and lost labor income versus indirect wealth effects from capital gains.

Economist Ben Harris warns that AI-driven growth may disproportionately benefit owners of capital rather than labor. Because capital income is taxed at a much lower marginal rate than labor income, this shift in the composition of national income would lead to lower-than-expected tax revenues, even amidst strong overall economic growth.

The US can grow its way out of its mounting fiscal problems through AI-driven productivity. This creates real growth without wage inflation, expands the corporate tax base, and offsets a poor demographic outlook. This is the most viable path for the US to avoid a fiscal cliff.