OLYMPIA — A bill introduced Monday by a group of Senate Democrats would prohibit the state’s attorney general from unilaterally taking legal action against the wishes of the governor or other agency heads.

Attorney General Rob McKenna angered state Democrats, including Gov. Chris Gregoire, by signing onto a multistate challenge to the national health care reform law.

Under the bill sponsored by Democratic Sen. Adam Kline, of Seattle, the attorney general would be required to seek consultation on matters not already covered by state statutes that grant the office authority to act on behalf of the state, such as consumer protection or fraud.

Fellow Democratic Sens. Karen Keiser, of Kent, Jeanne Kohl-Welles, of Seattle, and Karen Fraser, of Olympia, have also signed onto the bill.

The state Supreme Court ruled unanimously last September that McKenna has the authority to lead the state into a challenge against the health law, and McKenna’s office said he has not joined cost-sharing efforts in the multistate case because some state leaders disagreed with it.

McKenna, who is running for governor, believes the health care law is unconstitutional because of a requirement that people without health insurance must purchase private insurance or face a fine.

Gregoire, a Democrat, has said in a federal court brief that McKenna’s participation in the multistate lawsuit does not represent Washington’s position. She has moved ahead with plans to implement the health care law.

Last week, about 30 Democratic members of the Legislature filed a legal brief, joining other lawmakers from around the country, in asking the U.S. Supreme Court to uphold President Barack Obama’s health care overhaul. The U.S. Supreme Court will hear arguments on the case in late March, with an outcome expected in late June.

“There are a lot of people in the state of Washington who stand to gain from this act, and their attorney general is not representing their interests,” Kline said. “He’s doing it cowboy style, he’s doing it solo.”

Kline said that because the attorney general’s office and governor’s office are both open seats for election this year and could be won by either Republican or Democratic candidates, “it’s not a political matter.”

“It’s about governance,” he said. “It’s about proper relationships between attorney and client.”

McKenna spokeswoman Janelle Guthrie said that Kline’s bill impinges on the constitutional role of the attorney general.

“It’s the job of the Attorney General to balance the interests of individual state officials with the legal interests of the state and of the people as a whole,” she said in an email. “Sometimes that requires our office to take positions that are unpopular with other elected officials or individual state agencies. But to allow other officials to control the state’s legal interests, and those of other state agencies, would turn the Attorney General into a mere mouthpiece for those officials’ narrow interests.”

Kline’s bill also would codify a recent state Supreme Court ruling that requires McKenna to represent the state’s public lands commissioner in a legal appeal.

Justices ruled in September that McKenna can’t deny the commissioner legal representation. They said it was the first time the court had been presented with a case in which the attorney general had refused to represent a state official on an appeal.

Commissioner Peter Goldmark had argued that state law requires McKenna to provide legal aid upon request, but the attorney general refused to appeal a right-of-way case in Okanogan County. The county’s Public Utility District won a lower-court case allowing it to run power lines across state trust land that Goldmark manages.