With all of the notoriety being accorded negative advertising, it turns out that recent exchanges in Democratic debates have been tougher -- at least for now -- than the candidates' exchanges in their ads.

Witness a new spot in which Rep. Richard A. Gephardt (D-Mo.) goes after Democratic rivals Massachusetts Gov. Michael S. Dukakis and Sen. Albert Gore Jr. (Tenn.).

The ad, which began running this week in selected small cities and towns in targeted southern states, shows Rep. Marvin Leath (D-Tex.) standing with 34 other southern House members who support Gephardt. Leath tells viewers that Gephardt "stood with us" for lower taxes, an oil-import fee and a tough trade bill.

Then comes the attack: "On these issues, Gore and Dukakis were opposed to us. Gore and Dukakis even think the Gephardt trade amendment is too tough on the Japanese, Europeans and Koreans. We're tired of hearing that you can't fight for America anymore."

Gephardt campaign manager Bill Carrick said yesterday that the campaign has no plans to become tougher "unless it really gets nasty out there." Being held in reserve, however, is a southern version of a spot that worked for Gephardt in South Dakota.

The ad goes after Dukakis for lack of a trade policy and contends that he has raised taxes and that his idea of an agricultural policy is to tell farmers to diversify crops and grow flowers, blueberries and belgian endive.