HELENA, Mont. (AP) — Montana, a state that has long prided itself on strict campaign finance laws, is giving up on barring corporations from political spending and is instead attempting to expose every penny spent by them in elections.

Proposed rules released Wednesday to guide the state's expansive election law approved earlier this year would increase disclosure requirements for corporations and committees granted free-speech rights by the U.S. Supreme Court in its 2010 Citizens United ruling.

"This is an embracing of Citizens United," Montana Commissioner of Political Practices Jonathan Motl said Thursday about the new law. "They can speak, they can spend their money. They simply have to tell Montanans how much they're spending, who they spent it against or for, when they spent it and where they got that money from."

Montana is among the first states to require the level of disclosure, and other states are watching to see what effect it will have, Motl said.

"Other states are always watching Montana," he said. "It's a good show to watch."

Montana has been crafting the new law since 2012, when the Supreme Court used its Citizens United decision as the basis to throw out the state's century-old law that limited corporate election spending.

That 1912 law came in response to the corruption and election-buying that was notorious during the state's Copper King era.

Leaders in libertarian-minded Montana, citing recent cases in which legislative candidates were accused of illegally coordinating with a conservative group, sought a post-Citizens United replacement that would continue to prevent so-called dark money from influencing elections.

The new law has gotten opponents' attention. Attorneys who successfully petitioned the Supreme Court to throw out the 1912 law have already filed a constitutional challenge to the new law.

One of the problems with the law is that it broadens the definition of a political committee that is required to disclose spending and donors, said Anita Milanovich of the Bopp Law Firm.

That definition will now include groups not expressly advocating for or against a candidate. For example, a committee or corporation that releases an ad with a candidate's photograph and his views on an issue would be subject to the disclosure law, even if the advertisement doesn't recommend voting for or against the candidate, Milanovich said.

"If something like this were upheld, that would certainly attract the attention of other states looking to review their laws," she said.

Motl said the lawsuit means the new law will be tested for its constitutionality but will be in place and effective for the 2016 elections.

The draft rules face a public comment period and final approval before an Oct. 1 deadline.