In the battle for a chance to face incumbent Democratic U.S. Sen. Jon Tester in November, an outside group with deep pockets is making significant advertising buys in Montana’s Republican primary race – this time to support state Auditor Matt Rosendale– while targeting former state District Judge Russell Fagg of Billings.

The Super-PAC Club for Growth has targeted traditional Republicans– spending more than $3 million in a failed attempt to unseat Republican Sen. Thad Cochran of Mississippi for a tea party challenger in 2014– and almost $700,000 in 2016 to defeat Democratic candidate and former Wisconsin Sen. Russ Feingold. Their affiliated political action committee has endorsed Rosendale in the four-way Republican U.S. Senate primary, reportedly spending $632,000 on production and air time for one specific attack ad against Judge Fagg, which characterizes him as weak on sentencing convicted felons.