In an opinion that has not made it the most popular kid on the block with some of the country's political action committees, the commission has decided to enforce a law that prevents PACs from making more than $1,000 in independent expenditures in presidential general elections.

When the commission tried to enforce that ceiling in 1980, a three-judge U.S. District Court panel ruled that the limit violated the First Amendment and ordered that the limit be lifted. That freed independent political action committees, such as the National Conservative Political Action Committee, to spend about $12 million in the 1980 presidential campaign, most of it on behalf of President Reagan.

The case was appealed to the Supreme Court, which upheld the ruling on a 4-to-4 vote after the election was over. Given the tie vote, the FEC has now decided--on a 5-to-0 vote of its own--that it can go ahead and enforce the limits again in 1984.

"It's the height of bureaucratic tyranny for them to say they're going to enforce a law that the Supreme Court has struck down," said Robert Heckman, chairman of the Fund for a Conservative Majority, which hopes to spend about $5 million on Reagan's behalf in 1984. Undoubtedly, the whole issue is headed back to court.