WASHINGTON — The Supreme Court ruled today that Vermont's limits on contributions and spending in political campaigns are too low and improperly hinder the ability of candidates to raise money and speak to voters.

In a fractured set of opinions, justices said they were not sweeping aside 30 years of election-finance precedent but rather finding only that Vermont's law — the strictest in the nation — sets limits that unconstitutionally hamstring candidates.

The majority took issue with Vermont legislators for "constraining speech" by telling candidates and voters how much campaigning was enough.

President Bush's two appointees to the Court — Chief Justice John Roberts and Justice Samuel Alito — sided with the majority in overturning Vermont's law.

In one of six separate opinions, Justice Stephen Breyer said a majority of justices found Vermont's limitations on contributions and spending unconstitutional.

"That is to say, they impose burdens upon First Amendment interests that (when viewed in light of the statute's legitimate objectives) are disproportionately severe," Breyer wrote.

In 1997, Vermont passed its campaign-finance law, placing a $300,000 spending cap on gubernatorial candidates and lesser limits for other state political contests. Contributions to state campaigns were limited to as little as $200 per election cycle for state House races.

Several justices wanted to overturn the 1976 high court ruling Buckley v. Valeo but for different reasons.

Justices Anthony M. Kennedy, Clarence Thomas and Antonin Scalia have long wanted to overturn the case that they blame for much of the confusion in campaign-finance rules nationally.

But Justice John Paul Stevens said the 1976 ruling needs to be revisited because it did not deal squarely with the constitutionality of expenditure limits in campaigns.

Buckley made a distinction between limiting contributions and curtailing spending. The Court in that case said contributions to candidates' campaigns could be capped without infringing freedom of speech but that spending could not be limited because it could improperly reduce discussion of key issues.

Three lawsuits were filed challenging Vermont's limits by groups that included the Vermont Right to Life Committee, the Vermont Libertarian Party and the Vermont Republican State Committee.

Advocates for the Vermont law, considered one of the nation's strictest, argued that big-money contributors and unlimited campaign spending corrupt the political process.

Critics, however, said the limits on contributions and spending benefit incumbents. But Vermont's lawyers disagreed, saying the law allowed challengers to spend slightly more than incumbents.

During arguments in February, Vermont's attorney general, William Sorrell, said the limits helped politicians focus on campaign issues and their legislative duties rather than on raising large amounts of money.

The cases are Randall v. Sorrell, 04-1528, Vermont Republican State Committee v. Sorrell, 04-1530, and Sorrell v. Randall, 04-1697.