How much fiscal adjustment would stabilizing US debt require?
Core argument: Under the CBO forecast and current law, stabilizing US federal debt would require tax increases and spending cuts totaling 2.5% of GDP annually, with debt stabilizing at 122% of GDP if the measure took effect in 2034.
To understand this table, start with the CBO forecast and current law. Under these parameters, a combination of tax increases and spending cuts would need to total 2.5% of GDP annually to stabilize the debt. If this measure went into effect in 2034, then the debt would stabilize at 122% of GDP. The exact dollar figure of these required figures over the ten-year budget window used in Washington policy debates depends on the time path; the table shows the ten-year total—assuming that savings are linearly phased in from the first year to the full $1T in 2034—of $6T. Assuming higher productivity growth reduces these fiscal gaps, but some adjustment is still needed. This requirement is consistent with the observation that debt is still rising as a share of GDP even with productivity growth 0.5pp higher. If interest rates are higher, then an even larger fiscal adjustment is necessary. Under current policy, the tax cuts will be extended, adding about 1.6% of GDP to the needed adjustment. Overall, the needed fiscal adjustment ranges from 0.7% of GDP to 4.6% of GDP—which, if phased in, would amount to $2 to $11T over the ten-year budget window.



