The liberal National Committee for an Effective Congress launched a $2.5 million campaign, much of it aimed at defeating five conservative senators and 68 House members in 1982. It is the first time the nation's largest and oldest liberal political-action committee has committed a major part of its budget to defeating political opponents rather than boosting its own candidates.
But director Russell Hemenway told a news conference it will not carry on the kind of "negative campaign" that the conservative Committee for the Survival of a Free Congress used last year to help defeat six liberal Democratic candidates.
On Mr. Hemenway's list are Republican Sens. S. I. Hayakawa of California, William V. Roth Jr. of Delaware, Harrison H. Schmitt of New Mexico, Malcolm Wal lop of Wyoming, and Orrin G. Hatch of Utah.