OLYMPIA — State Attorney General Rob ­McKenna said Monday that he will join a multistate challenge to the constitutionality of the health care overhaul bill being passed by Congress.

The announcement by ­McKen ­na, a Republican, immediately angered Democratic Gov. Chris Gregoire, who said that McKenna did not consult with her, House Speaker Frank Chopp or Senate Majority Leader Lisa Brown — all Democrats — before making his decision.

“I don’t know who he represents,” Gregoire said.

“He doesn’t represent me.”

As the chief legal officer for the state, the attorney general typically represents state officials or agencies.

However, he is a statewide elected official who, under state law, can bring lawsuits on behalf of the citizens of the state.

‘New requirements’

McKenna said he believes the measure passed Sunday night by the House “unconstitutionally imposes new requirements on our state and on its citizens.”

The measure would extend coverage to 32 million uninsured Americans and, for the first time, most would be required to purchase insurance and face penalties if they refused.

McKenna said the requirement for people to buy health insurance was an “unprecedented federal mandate” that violates the commerce clause and the 10th amendment of the U.S. Constitution that deals with state sovereignty.

He and other attorneys general argue that the commerce clause, which was intended to allow the free flow of goods among the states, is not broad enough to allow Congress to require citizens to purchase goods or services, such as health insurance, that they might not want.

He also argued that the measure puts an extra burden on Washington state’s budget by requiring the state to expand its Medicaid eligibility standards.

Gregoire didn’t know

Gregoire said she didn’t learn about McKenna’s intentions until Monday morning, when she read an article that listed him among attorneys general who planned to sue. She said she called McKenna immediately to ask if it was true.

Gregoire said she told him “then get ready to represent me, because I will legally oppose what you’re doing.”

She said that once the lawsuit is filed, she will file a brief in opposition.

Gregoire was attorney general before ­McKen ­na.

Gregoire spokesman Cory Curtis said the governor would likely have to get an attorney outside of the Attorney General’s Office if she takes legal action opposing McKenna’s lawsuit.

The governor said she believes McKenna has a duty to consult with her and with House and Senate leadership before deciding to sue the federal government.

She said that if he had called her, she would have told him about the benefits of the health care bill to the citizens and businesses in Washington state.

State Insurance Commissioner Mike Kreidler, also a Democrat, issued a release Monday saying the health care measure will cut the number of uninsured in Washington state by more than 500,000 by 2014.

McKenna’s “attempt here to undermine that benefit is just wrong,” Gregoire said.

A Facebook page created Monday called “Washington Tax Payers OPT OUT of Rob McKenna’s lawsuit” had more than 260 followers by the afternoon.

A companion package making a series of changes sought by U.S. House Democrats to the main overhaul bill, which already had passed the Senate, was also approved Sunday night by the House.

That bill now goes go the Senate, where debate is expected to begin as early as today.