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Democrats in Arizona are celebrating today after the state’s Supreme Court ruled Thursday to reinstate the head of Arizona’s Independent Redistricting Commission.

Republican state legislators, led by GOP Gov. Jan Brewer, voted to oust Chairwoman Colleen Mathis, an independent, earlier this month after Mathis voted with Democrats to approve a redistricting map that could strap at least one GOP House member with a more  competitive re-election bid and give Democrats a clear shot at the state’s new district.

“Gov. Jan Brewer and her GOP accomplices in the state Senate attempted to usurp the redistricting process by illegally removing the independent redistricting chairwoman,” Michael Sargeant, the Democratic Legislative Campaign Committee’s executive director, said in a statement following the ruling. “Thankfully, this naked power grab ultimately met with failure as the Supreme Court overrode the Republicans’ actions.”

The governor’s office issued a statement Thursday night, calling the decision “deeply regrettable.” Brewer justified her decision to remove Mathis, saying she’d conducted too many meetings behind closed doors and was “disregarding mapping criteria seemingly at will.”

“With today’s decision, the court has substituted its judgment and authority for that which the voters specifically assigned to the governor,” Brewer said in the statement. “The chairwoman’s actions to meet in secret, arrange critical votes in advance of meetings and twist the words and spirit of the Constitution have been forgiven – if not endorsed outright. In the coming days, I’ll be considering my options as to how best to proceed.”

David Berman, a senior research fellow at Arizona State University’s Morrison Institute for Public Policy, said the court’s decision dealt  a “devastating blow” to the governor.

“From the opinion that came down last night, the court seems to be pretty definitive on dismissing the arguments the governor was making,” Berman said. “The governor didn’t like the map is pretty much what it came down to, and that is no justification for [removing the chairwoman] under the Constitution.”

With Mathis reinstated, Berman said the commission is likely to approve a map “very quickly,” which would make the right-leaning state more competitive for Democrats.

Republicans currently hold a 5-3 majority of the state’s House seats. In the new map, under which Arizona gains one representative, Berman said the GOP is basically “guaranteed” four seats and has a “good shot” at three more. Under the “best of conditions,” he said, Democrats could pick up five of the state’s nine House districts.

“I wouldn’t call it a Democratic map,” Berman said. “What the map does overall is increase competition. It could make it easier for Democrats to come up with victories but really wouldn’t guarantee anything.”

Arizona is the latest example of Democrats coming out on top in states whose  redistricting maps were pushed into the courts.

In Colorado last week, a Denver district judge selected a Democrat-drawn map that could deal two Republican representatives tough re-election bids. Republicans may challenge the decision.