The Washington Post is credited with exposing the Watergate conspiracy and helping to bring down a corrupt presidency. Forty years later, the Post played a role in the corruption of the Internal Revenue Service, to the benefit of an incumbent president in a bitter and close re-election.

A staff memo released earlier this week by the House Oversight and Government Reform Committee provides an "interim update" on the investigation of the IRS scandal. A central finding: "Media attention caused the IRS to treat conservative-oriented...