Following up on a recent blog post by my colleague Matt on interest expense, I wanted to point out yesterday's report by the Treasury that the government's net interest payments on the national debt reached $226.6 billion in FY 2006, an increase of 23 percent over FY 2005. (See the Monthly Treasury Statement, Table 9.) Put another way, almost all of of the last fiscal year's $248 billion federal deficit is accounted for by interest expense. Some of the increase itself results from markets and monetary policy (yielding higher interest rates). But less-than-responsible fiscal policy in recent years has pushed federal interest payments up to the point where a vast proportion of the deficit reflects the dead-weight expense of paying down the cost of the debt.