Justices Assail 'Millionaires' Amendment'

Roberts expressed reservations about the part of the law that required greater and more frequent disclosures for the wealthy candidate than for his or her opponent.

Justice Samuel A. Alito Jr. said that if Congress believes that a $2,300 contribution limit is necessary to prevent the perception of corruption, why would it think it acceptable to allow the opponent of a wealthy candidate to raise three times as much?

Solicitor General Paul D. Clement, representing Congress in defense of the law, called Congress's solution an "adjustment of interests." It is an attempt to level the playing the field without violating the court's long-held ruling that a candidate cannot be restricted in how much he spends on his own campaign, he said.

Clement told Roberts that the disclosure requirements are not much greater than those imposed on other campaign spending. And he agreed with Justice Stephen G. Breyer that if a majority of the court shared Kennedy's concern about party spending, that part of the law could be severed without disposing of the entire amendment.

Campaign finance questions seem to expose the philosophical divisions on the court, which upheld key provisions of the McCain-Feingold act in 2003 with a massive, 5 to 4 decision. Last year, with Roberts and Alito on the bench, it voted 5 to 4 to loosen a critical part of the law regarding corporate and union financing of broadcast advertising.

And six justices felt the need to write opinions when the court in 2006 considered Vermont's stringent limits on campaign contributions.

The case, Davis v. Federal Elections Commission, will be decided before the court adjourns at the end of June.