The Supreme Court yesterday struck down as unconstitutional a post-Watergate reform that limited the amount of money political action committees could spend on behalf of presidential nominees.

The court said a $1,000 spending limitation on such committees, or PACs, is an impermissible infringement on First Amendment rights of free speech and association.

The ruling is a major victory for conservative PACs, such as the National Conservative Political Action Committee (NCPAC) and the Fund for a Conservative Majority, whose expenditures were challenged by the Democratic Party and the Federal Election Commission. The decision removes limits only from spending by PACs for activities of their own in support of presidential nominees in general elections.

It leaves intact regulations on how much individuals may contribute directly to candidates seeking their party's nomination or to PACs. And it does not affect a prohibition on private contributions to party nominees who qualify for and accept public funding for the general election campaign.

As a result, individuals remain limited to contributions of $5,000 a year to each of five PACs for a total of $25,000 or $1,000 to each of 25 candidates -- presidential or congressional -- per election. PACs and individuals, however, have no limits on what they may spend independently for or against any candidate in a congressional or presidential campaign.

Justice William H. Rehnquist, writing for the 7-to-2 majority, said that "allowing the presentation of views while forbidding the expenditure of more than $1,000 to present them is much like allowing a speaker in a public hall to express his views while denying him the use of an amplifier."

Rehnquist said that "preventing corruption or the appearance of corruption is the only legitimate or compelling government interes w0070 ----- r a BC-03/19/85-COURT 1stadd w0070 03-19 A01 organization will "continue to explore legislative remedies" to deal with the impact of independent expenditures on presidential campaigns.

Such expenditures mushroomed after Congress enacted laws in the early 1970s and again after Watergate to control campaign spending and contributions. PACs spent very little in the 1976 presidential election, but spent $13.7 million in the 1980 general presidential election -- nearly $13 million of that for Ronald Reagan. In 1984, PACs spent about $17 million in the general presidential campaign, with about $16 million going for Reagan. In 1984, both major party candidates also received $40.4 million in federal campaign funds.

Pending the definitive ruling by the Supreme Court, the FEC had not enforced the regulation struck down yesterday. The court took up the issue in 1982 but split 4-to-4 in a similar case, leaving the constitutional question unresolved.