A group affiliated with the billionaire conservative donors Charles and David Koch will launch a six-figure ad buy on Thursday targeting Sen. Jon Tester Jonathan (Jon) TesterPence seeks to boost Daines in critical Montana Senate race This World Suicide Prevention Day, let's recommit to protecting the lives of our veterans Filibuster fight looms if Democrats retake Senate MORE (D-Mont.), who is among the most vulnerable Democrats up for reelection in 2018.



Americans for Prosperity is putting about $560,000 behind TV and digital ads that will run across Montana saying that Tester, who voted for ObamaCare, has not done enough to address rising healthcare costs across the state.



“Montana families struggle to make ends meet. Our biggest worry — rising healthcare costs,” the narrator in the ad says. “Sen. Jon Tester knows that and he knows ObamaCare isn’t working. He even says he regrets not making it better. So did he vote to fix it? No, he voted again and again to keep the mess ObamaCare created.

ADVERTISEMENT

"He voted to keep ObamaCare’s devastating tax penalty, putting partisan politics ahead of our care. Tell Jon Tester — support better healthcare at lower costs.”The Koch Network will spend up to $400 million on politics and policy ahead of the midterm elections, although the groups have recently expressed frustration with the GOP-controlled Congress for putting major legislation on hold until after the elections.Ad buys from AFP and other groups have focused primarily on attacking Senate Democrats in states thatcarried in 2016. There are 10 Senate Democrats seeking reelection in those red states, providing Republicans with an opportunity to hold the Senate despite the tough political environment for the GOP.Trump won Montana by 21 points. Tester won both of his previous elections with less than 50 percent of the vote.Tester has argued that he’s willing to work with Trump, touting the 13 bills he supported that Trump signed into law in his first reelection campaign ad.Still, Tester did not support the GOP tax cuts bill. His Republican challengers — state auditor Matt Rosendale, Judge Russ Fagg and businessman Troy Downing – have been attacking him over that issue. And now AFP is looking to turn healthcare into a liability as well.“For too long, Montana families have listened to Senator Tester promise relief from skyrocketing health care costs. But what they’ve gotten instead is a lot of empty rhetoric and costs that continue to rise,” said AFP president Tim Phillips.“Senator Tester made a promise to look out for the people of Montana, and that should start with giving hardworking families and individuals more choice over their health care decisions.”