[[nid:139646]]In a move that puts her at odds with Colorado Gov. John Hickenlooper, state Attorney General Cynthia Coffman says she’s weighing whether to go to court to challenge a new federal rule aimed at cutting carbon emissions at coal-fired power plants. 

She says the federal goal to reduce carbon emissions by 32 percent over the next 15 years raises "significant concerns for Colorado" and called the federal targets set for Colorado “unrealistic.”

"As I put the best interests of Colorado first, it may become necessary to join other states in challenging President Obama’s authority under the Clean Air Act," Coffman said. 

Gov.  Hickenlooper has said he intends for the state to comply with the new federal rule. Meantime, the environmental group Western Resource Advocates released its assessment Tuesday saying Colorado is well poised to meet the new federal goals.

A spokesperson for Coffman did not have a timeline for when she will decide whether to join other states in challenging the rule.