The ad war in the Montana governor’s race is officially on, with a group affiliated with the Democratic Governors Association going up with an ad responding to Republican attacks.

A state GOP ad earlier this week, partially funded by the Republican Governors Association, hit state Attorney General and presumptive Democratic nominee Steve Bullock for not joining on to a lawsuit, filed by other state attorneys general, that seeks to overturn President Obama’s health care law.

In response, the Democrats’ ad, from the DGA-affiliated group Montana Jobs, Energy, and Technology (JET) PAC, says Bullock saved the state thousands of dollars by declining to take part in the suit.

“Health care will be decided by the Supreme Court,” the narrator says. ”Thanks to Attorney General Steve Bullock, Montana didn’t have to spend a dime of taxpayer money to make sure that happens. Bullock stood up to the politicians who wanted to spend thousands of your tax dollars on a political lawsuit.”

The ad closes by saying that Montana is one of the best-run states in the country, “and only Steve Bullock has the guts, experience and commons sense to keep it that way.”

The DGA would not disclose the size of the ad buy, only to say that it is significant and statewide.

The GOP’s ad buy was reported at $140,000.

The Republican primary is crowded, with former congressman Rick Hill leading the way so far on the fundraising front.