Political activists representing liberal and conservative philosophies yesterday announced a series of law suits to challenge the constitutionality of certain parts of the federal Election Campaign Act.

At a news conference, they said the first lawsuit, filed in U.S. District Court yesterday, is designed to strike down limits on contributions to groups for independent spending. Independent spending involves outlays to advocate the election or defeat or candidtes without consulting the candidates or their campaign organizations.

Other areas of the law to be challenged in coming weeks include contribution limits applied to challenging candidates and minority parties, the annual limit on what an individual may contribute to all candidates and committees, and the interpretation of law that gives a wealthy candidate an unlimited ability to contribute to his or her own campaign, the group of activits said.

The coalition is led by former Democratic senator Eugene McCarthy, a liberal who ran for president in 1968 and 1972, and conservative Sen. Gordon Humphrey (R.-N.H.). They are allied with groups ranging from the Conservative Victory Fund to the Libertarian Party and the Ripon Society.

McCarthy and Humphrey said the spending limitations in the election laws and interpretations of various provisions by the Federal Election Commission have limited an individual's constitutional right of freedom of expression.

Humphrey said the spending limits and FEC interpretations help keep incumbents in office and have made it virtually impossible for an unknown candidate to win.

McCarthy said, "I see a very fundamental philosophical problem with whether a political party can agree only to communicate so much to the people." w

He said limitations on how much an individual can contribute to a campaign and on how much a candidate can spend restrict both freedom of speech and "the right of the people to know."

John Topping, president of the liberal Ripon Society, said the groups have a "common feeling that there has been a tendency by the FEC to overreach itself" and that as a result it has given an "enormous advantage to incumbents and made it difficult for someone who is not a celebrity or a millionaire to run."