The Supreme Court will hold a special, one day session tomorrow to examine whether an overhaul of the nation's campaign finance laws violates the Constitution's right to free speech.
The decision will govern how campaign money is raised and spent in the upcoming election, and the ones that follow.
At issue is the so-called "McCain-Feingold" law, which bans large, unregulated soft-money donations to political parties -- and imposes tighter advertising controls in the weeks before an election.
Opponents say the law violates the Constitution because it silences donors and political parties.
Supporters say it simply refines rules the court already found constitutional in 1976, when it upheld anti-corruption regulations.
With reservations, President Bush signed the bill into law last year, saying it was an improvement over the current system. Within hours, court challenges to the law were filed.
Experts expect a ruling before the first presidential primary in January.