The House unexpectedly flipped on a Republican proposal to bring charter schools to Montana.
The chamber shot the measure down 50-49 on a vote Tuesday needed to advance it to the Senate - just a day after endorsing it in an initial vote.
A Republican leader backing the measure said he was surprised that some in his caucus switched their votes, and was uncertain whether the measure would be revived.
School and education groups had been lobbying against the measure. The opponents argued that the charter schools establish a parallel school system that would siphon money out of traditional public schools.
Supporters of House Bill 315 said the new charter schools would be exempt from most state regulation in exchange for greater requirements to produce results.