Former U.S. Transportation Secretary and 2020 presidential candidate Pete Buttigieg speaks in support of a proposed ballot initiative, known as the "Montana Plan," that would exclude corporate money from Montana politics, at The Mother Lode Theatre in Butte, Montana, May 17, 2026.

Janie Osborne | Getty Images

Imagine a corporation wants to spend $10 million to defeat a political candidate. Under the Supreme Court's landmark 2010 Citizens United ruling , it can spend as much as it wants provided it doesn't coordinate with the candidate's campaign.

On Tuesday, Montana voted to change that.

In a state President Donald Trump won by nearly 20 points in 2024, roughly 65% of Montanans voted to approve Initiative 194 — the "Montana Plan" — embracing a novel legal strategy to curb corporate political spending.…