Washington is struggling to make a deal that will couple an increase in the debt ceiling with a long-term reduction in spending. There is no reason for the players to make their task seem even more Herculean than it already is. But we should be prepared for upward revisions in official deficit projections in the years ahead—even if a deal is struck. There are at least three major reasons for concern.
First, a normalization of interest rates would upend any budgetary deal if and when one should occur. At present, the average cost of Treasury borrowing is 2.5%. The average over the last two decades was 5.7%. Should we ramp up to the higher number, annual interest expenses would be roughly $420 billion higher in 2014 and $700 billion higher in 2020.
The 10-year rise in interest expense would be $4.9 trillion higher under “normalized” rates than under the current cost of borrowing. Compare that to the $2 trillion estimate of what the current talks about long-term deficit reduction may produce, and it becomes obvious that the gains from the current deficit-reduction efforts could be wiped out by normalization in the bond market.