By Martin Kidston/Missoula Current

A national grassroots organization intent on reversing the Citizens United ruling gave its official support to U.S. Sen. Jon Tester on Thursday, even though his bid for reelection is still more than a year away.

End Citizens United said Montana's senior senator has established a track record of fighting the U.S. Supreme Court's controversial Citizens United ruling, and has worked to reform the campaign finance system.

Tiffany Muller, executive director of the Washington, D.C., organization, said Tester represents Montana's long-standing tradition of supporting transparent and clean elections. She expects dark money groups to flood the state with misleading advertising as the election nears.

“There's no stronger champion working to get big money out of politics than Sen. Tester," Muller said on Thursday. "He knows that our democracy works best when it puts people first – not corporations and big special interests. We're proud to stand with Tester, and we look forward to fighting alongside him to take on the rigged system and give all Montanans and Americans a voice.”

End Citizens United was established in March 2015 to counter the negative effects of Citizens United and reform the nation's campaign finance system.

Since the Supreme Court ruling, Tester has introduced several bills in the U.S. Senate aimed at exposing dark money in politics and passing a constitutional amendment that would overturn Citizens United by stating that corporations are not people.

Tester also opposed Supreme Court Justice Neil Gorsuch's nomination to the bench, citing what he described as the judge's extreme position on money in politics. Since then, according to Muller, dark money groups have dumped nearly $1 million in Montana advertising attacking Tester's position.

Asked why End Citizens United was announcing its endorsement so early, Ann Feldman said that doing so would connect Tester's campaign with her organization's grassroots members and elevate campaign finance as a critical election issue.

Tester, who was first elected to office in 2006, does not yet have an opponent in Montana, though that's likely to change in the coming months as the 2018 election draws closer.

"Tester has long been a champion of campaign finance reform and Montana is going to be a top priority for us this cycle,” Feldman told the Missoula Current in an email. “By getting into this race early, we can activate our grassroots network as soon as possible to fight back against the corporate special interest money that we expect to pour into the state."

Last week, End Citizens United announced that it has raised $4 million in the first quarter of 2017. It projects that it will raise $35 million for the 2018 cycle, surpassing the $25 million it raised for the 2016 elections.