
There were many happy faces in Washington on Friday with the Treasury Department’s announcement of robust tax revenues for April. Individual income-tax receipts surged to $240 billion for the month, taking the total for 2013 to $483 billion. This is far greater than the $393 in tax revenues the federal government collected for the first four months of 2012. The increase far surpassed the Congressional Budget Office projections in February.

The influx surprised the CBO and many other observers, but it shouldn’t have. Neither should the dramatic drop that is likely to follow, though policy makers will be tempted to behave as if the revenue flood will continue.