The US Supreme Court has struck down federal limits on how much political parties may spend in coordination with candidates, a ruling that could significantly alter the financial structure of federal election campaigns.

In National Republican Senatorial Committee v Federal Election Commission, the court held that limits on coordinated party expenditures violate the First Amendment. The case challenged provisions of the Federal Election Campaign Act that restricted spending by party committees when that spending was coordinated with candidates.

The decision gives national and state party committees wider room to work directly with candidates on campaign activity, including advertising and voter outreach. Supporters of the challenge argued that the rules burdened core political speech and weakened parties compared with outside groups. Defenders of the limits warned that removing them could make parties a larger channel for donor influence.

The ruling lands ahead of a high-stakes election cycle and is likely to intensify debate over the role of money in US politics. Political parties may now be able to direct more resources into closely coordinated campaigns, potentially reducing the relative importance of some outside spending groups while increasing pressure on donors, party committees and candidates to align strategy.

The court’s opinion focuses on constitutional protection for political speech. Its practical effects will depend on how quickly party committees adapt, how the Federal Election Commission interprets remaining rules, and whether Congress attempts a narrower replacement framework.

For voters, the immediate result may be more campaign spending that is formally tied to party organisations rather than nominally independent groups. For regulators, the decision removes one of the older guardrails in the federal campaign finance system and leaves new questions about disclosure, coordination and donor access.