Richard Cohen, president of the Southern Poverty Law Center, was to testify before the House Homeland Security Committee about threats posed by domestic extremist groups. The hearing, scheduled for Tuesday, has been postponed because of Hurricane Irma. As a black conservative who has been smeared by the SPLC, I recommend against reinviting Mr. Cohen.

When Morris Dees and Joseph J. Levin Jr. started the SPLC in 1971, it was needed and it had noble goals. In recent years, however, it has become a tool of the radical left. Domestically,...