Washington ? When the Supreme Court returns from its summer recess today, it will take up a campaign finance reform case so complex and controversial that supporters and opponents can’t even agree on what Congress was trying to achieve when it passed the historic election spending law.

The court will hear arguments on whether Congress went too far when it passed the Bipartisan Campaign Reform Act of 2002, the first major campaign finance legislation in 30 years.

For supporters, the law was designed to end a system of massive cheating in the funding of federal election campaigns and close loopholes that allowed corporate and individual donors to funnel tens of millions of dollars to campaigns.

For opponents, the law is an obvious violation of the First Amendment and will diminish the free speech rights of political parties, corporations and labor unions. In passing the law, lawmakers weren’t trying to protect the system from corruption, they say, but instead were looking out for their own interests and seeking to stifle criticism of federal elected officials.

Reflecting the significance of the case, the court agreed to return to the bench in September, a month before it formally opens its 2003 term, in order to produce a decision that will govern how candidates and parties raise money for the 2004 presidential campaign.

At issue are two key provisions of the law.

The first section bans political parties from accepting unlimited contributions from corporations, unions or individuals — the “soft money” donations that total hundreds of millions of dollars.

The second contested provision blocks corporations and unions from spending money out of their general funds to broadcast advertisements close to Election Day that mention a particular candidate and are designed to influence the election. Under the law, such ads can only be paid for by the company or union’s political action committee.