HELENA (AP) — A state judge on Wednesday ordered Republican gubernatorial candidate Rick Hill to stop spending a contested $500,000 donation while its legality is under review, and to cancel the ads already bought with the money.

District Judge Kathy Seeley of Helena issued the temporary restraining order shortly after the case was returned from federal to state court.

It gives Hill’s Democratic opponent, Steve Bullock, a big win in his challenge of the donation to Hill from the Montana Republican Party.

The donation far exceeds the $22,600 that Hill would normally be allowed to collect from all political parties combined. The former congressman argues the donation was legal because it came after U.S. District Judge Charles Lovell tossed out the state’s contribution limits Oct. 3, but before an appeals court reinstated those limits six days later.

Shortly after receiving the Oct. 5, donation from the Montana Republican Party, Hill spent more than $620,000 on new advertising — including one purchase of $392,881 on Oct. 16.

Seeley’s temporary restraining order says Hill is prohibited from spending any campaign contributions in excess of the $22,600 permitted, and that all television and radio advertisements that have been purchased with the donation must be canceled.

The Hill campaign was reviewing the ruling and did not have an immediate comment.

Bullock campaign manager Kevin O’Brien said he hopes Hill will respect the integrity of the election and do the right thing.

“By law he has to comply with the TRO. And I believe he’ll have to return the money, too” O’Brien said.

Bullock sued Hill last week, arguing Montana contribution limits are aggregate over the course of a campaign, and now that the legal limits are reinstated, they are in force for the entire election cycle. That includes the brief window when federal courts had tossed the state’s contribution limits, he said.

“The limits do not merely regulate one-time behavior,” Bullock attorney Jonathan McDonald wrote. “They are ongoing; they are continuous; they are perpetual from the beginning to the end of the campaign.”

Hill asked the federal courts to take over the case because that is where the legal dispute over the constitutionality of the state’s contribution limits has been playing out. But U.S. District Judge Dana Christensen wrote in an order Wednesday the case belongs in state court

“Interpretation of the statute is a matter of state law, and the state court is better suited to engage in that exercise,” the judge wrote.

Conservative groups trying to dismantle the contribution limits are asking Lovell, the federal judge, to find Bullock in contempt for filing his lawsuit. Lovell has not ruled on that request.