"I wish they would have spent more time thinking about it," Bullock said.
The measure's supporters said it would put money in the hands of Montana workers and bolster local economies with tax breaks for businesses that abide by the law.
Curtis said neighboring states have even more stringent mandates: Idaho requires that 95 percent of public-works laborers are state residents, while Wyoming and North Dakota have similar rules.
"We are just trying to encourage businesses to do the right thing and hire Montana workers," Curtis said. "I think that our workers are worth more."
Montana union members called it a "commonsense bill." John Forkan, speaking on behalf of the Montana State Associations of Plumbers and Pipe Fitters, cited the measure's economic and employment benefits.
"It allows for some tax abatement considerations for employers," Forkan said. "It will put Montanans back to work on Montana projects."