There can be no ambiguity about Sen. Metzenbaum's liberal credentials. He was one of four Democratic senators with a perfect liberal voting score, according to National Journal's vote rating of Congress members last year. The three others are Paul Simon (Ill.), who also is to speak at the CDV conference, John F. Kerry (Mass.) and Alan Cranston (Calif.).

Republican senators with perfect conservative scores were Steve Symms (Idaho), Malcolm Wallop (Wyo.) and Phil Gramm (Tex.).

National Journal's ratings, based on 48 key recorded votes in the Senate and 58 in the House, showed each member's stance in relation to his or her colleagues.

Perfect liberal scores in the House were compiled by Democrats Don Edwards (Calif.), Augustus F. Hawkins (Calif.), Jose E. Serrano (N.Y.) and Sidney R. Yates (Ill.).

The most conservative House members, all Republicans, were John Hiler (Ind.), defeated in November, and Carlos J. Moorhead (Calif.).

Of the five senators and one House member most often mentioned as potential 1992 Democratic presidential candidates, Sen. Albert Gore Jr. (Tenn.), considered the most conservative in the 1988 Democratic field, is the most liberal this time, according to the rating. He is followed by Gephardt, Sens. Bill Bradley (N.J.), Bob Kerrey (Neb.), Lloyd Bentsen (Tex.) and, far down the liberal scale, Sam Nunn (Ga.).