Hearing a case that could have broad ramifications for future elections across the country, the Supreme Court yesterday considered whether limits on individual contributions to political campaigns violate free speech rights.

The case, involving a Missouri cap on contributions to state races, arises as the cost of political campaigns continues to spiral upward and Congress is again wrestling with campaign finance reform.

The closely watched dispute represents the first major challenge to the court's 1976 decision in Buckley v. Valeo, which allowed the federal government to limit how much people give to candidates but struck down restrictions on how much candidates may spend on their own campaigns, saying the latter unconstitutionally infringed political expression. But while some of the justices criticized the confusing standards of Buckley, there appeared to be no overriding sentiment to strike it down.

Nonetheless, the justices appeared deeply divided on whether to uphold the Missouri law, which restricts the amount individuals can give to candidates for state offices and is similar to the $1,000 cap on individual contributions in federal law and to campaign limits in many other states and cities. Should the court invalidate the Missouri limits, it would provide ammunition to those who would challenge contribution limits elsewhere.

Yesterday's arguments were remarkably spirited, with all nine justices jumping into the fray. In attendance in the packed courtroom were several members of Congress with stakes in the battle on the Hill, including Sen. Mitch McConnell (R-Ky.), who has fought campaign finance restrictions; and Sens. Russell Feingold (D-Wis.), Jack Reed (D-R.I.) and Harry M. Reid (D-Nev.), who have backed greater restrictions on political money.

Up first was Missouri Attorney General Jeremiah W. Nixon, defending the 1994 state law that allows individuals and political committees to give no more than $1,075 to candidates for statewide office. He emphasized the public perception of corruption when politicians get large sums of money and argued that without contribution limits people would think "their government is for sale."

But Chief Justice William H. Rehnquist suggested that if a state is going to limit contributions, it must be able to present specific evidence that money has distorted the political process, rather than just the public's perception that it is a corrupting influence. Other justices observed that, in contrast with the federal caps, which were adopted in 1974 in response to the extensive findings of corruption during Watergate, the Missouri law was based on scant evidence.

"Do you seriously think there is a risk of corruption or the appearance of corruption if you let someone give more than [the limit]?" Justice Antonin Scalia asked.

Justices Sandra Day O'Connor and Anthony M. Kennedy, likely key votes in the case, emphasized that the burden was on the state to justify any curtailment in free political speech. But Kennedy also expressed concern about a political system obsessed with money, noting, "We've seen Buckley hasn't worked very well."

More sympathetic to Missouri's position, Justice David H. Souter said, "Most people assume, and I certainly do, that someone making an extraordinarily large contribution is going to get something extraordinary in return." In a similar vein, Justice Ruth Bader Ginsburg added that she was disturbed by the notion that in the absence of contribution limits, a candidate might want to rely on one big contributor and forget the rest of the public.

The Clinton administration, represented by Solicitor General Seth Waxman, sided with Missouri.

Representing the challengers to the Missouri limits, D. Bruce La Pierre told the justices the American people should be trusted to decide which candidates shouldn't be elected because they owe something to their big donors. "The government should not limit the voice of some to amplify the voice of others," he said.

The case was originally brought by Zev David Fredman, a failed candidate for state auditor, and by the Shrink Missouri Government PAC, which backed his campaign. They argued that effective campaigns couldn't be mounted, particularly against incumbents, unless challengers were able to draw larger contributions. An appeals court struck down the limit, calling it a "heavy-handed restriction of protected speech."

The case of Nixon v. Shrink Missouri Government PAC is being closely followed by special interest groups on both sides of the issue. Campaign finance reformers and a majority of the states have asked the court to use it to permit greater restrictions on contributions and possible new ones on spending. But some civil libertarians and others who believe that contribution limits hurt challengers want the court to lift all caps. A ruling is expected by next summer.