OLYMPIA — The wait is over.

Tonight, Republican Attorney General Rob McKenna is expected to launch his campaign to become Washington’s next governor in 2012.

His announcement is scheduled to come at a 6 p.m. event in t

he Performing Arts Center at Sammamish High School in front of supporters invited over the past several days by phone and email.

“I’ll be there. I think he has a great opportunity to win,” said Rep. Mike Hope, R-Lake Stevens, who learned of plans from a McKenna aide Monday. “He has a demonstrated leadership ability and that’s what we need right now.”

McKenna is expected to declare for a race without knowing who will be his main Democratic opponent.

Democratic Gov. Chris Gregoire is wrestling with whether to seek a third term in office.

She said Tuesday she could decide before heading to the Paris Air Show next week and will “absolutely” do so by the end of the month. She said she will spend time this weekend talking it over with her husband and two daughters.

“I respect the fact that I need to make a decision soon, and I commit to you all I will,” she told reporters. “If for nothing else, so you guys won’t ask me.”

McKenna did call her Tuesday, but she wouldn’t divulge the subject. He did not return phone calls, and his advisers declined to answer questions.

“If he’s going to make an announcement, then he’s entitled to make it on his own terms,” she said.

Should Gregoire not seek re-election as most political observers expect then U.S. Rep. Jay Inslee, D-Wash., will almost certainly declare his candidacy.

“Jay is giving serious consideration to running if the governor decides to not seek another term. He’ll make his decision sometime after her announcement,” said Joby Shimomura, political director for his congressional campaign.

It’s been on his mind for months. An invitation to a March 20 fundraiser in Mukilteo said Inslee was trying “to put some funds in the bank early for his congressional race and also if there is an opening to run for governor.”

McKenna is getting a jump on them both as he seeks to become the state’s first Republican governor since John Spellman in the ’80s. He called the former governor Monday night to share his plans.

“I appreciated it,” said Spellman, 84, who served from 1981-85. “I have known him for some time. I think he’s got a good shot. It’s been a very long wait.”

There have been close calls, most notably Dino Rossi’s razor-thin defeat in 2004 — a contest many Republicans still feel he won. Republicans think 2012 may provide an even better shot than eight years ago.

Alex Hays, executive director of Mainstream Republicans of Washington, said voters know McKenna well from his two statewide races. And, he said, the public is tiring of Democrats controlling the governor’s office and the Legislature.

“Washington state has suffered terribly under one party rule,” he said. “Even Democrats, the honest Democrats, realize it’s time for reform in Olympia, and it cannot happen with one party rule.”

Hays contended Democrats are “terrified” of McKenna who has established himself as a gracious and likeable political moderate.

“He is a no-nonsense, take-care-of-the-people’s-business centrist,” he said

Democrats have been preparing for what will be a difficult and expensive battle to defeat McKenna.

Months ago, the state Democratic Party set up a faux “Rob McKenna for Governor” web site to attack his record and political persona.

“Today’s announcement comes as no surprise, because Rob McKenna has spent the last six years running for governor,” state Democratic Party chairman Dwight Pelz said. “He is a very conservative Republican running in a blue state who will try to mask himself as a moderate.”

Democrats lambast McKenna most for his decision to join a multi-state lawsuit challenging the constitutionality of the 2010 federal health care reforms. They portray McKenna’s action as politically calculated to win support from the tea party movement.

McKenna has said his target is the law’s mandate requiring all Americans to purchase government-approved health insurance. It violates the rights of states to set their own rules, he has said.

Meanwhile, leaders of organized labor are gearing up their fight against the Republican candidate with a conference call scheduled for this morning with reporters.

They contend in a press release issued Tuesday that McKenna’s actions in his political career “seem to indicate that Washington workers would not fare well under his leadership as governor.”

McKenna, 48, is married and the father of four children. An Eagle Scout, his political career began with his 1995 election to the King County Council. He ran unopposed for re-election in 1999 and 2003.

In 2004, he ran for attorney general after Gregoire, who held the job, opted to run for governor.

McKenna defeated Democrat Deborah Senn in 2004 and walloped Democrat John Ladenburg in 2008. In both races, Snohomish County voters overwhelmingly backed McKenna.

Money is going to be a huge factor. Gregoire and Rossi spent a combined $25.3 million in their rematch while outside groups spent another $20 million on their own.

At this point, McKenna has about $400,000 in the bank, according to state campaign reports. Gregoire is sitting on pretty much nothing. Inslee has $1.2 million on hand for his congressional race, which he should be able to move over.

Reporter Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.

Past races

Rob McKenna was elected attorney general in 2004 and re-elected in 2008. In both races, he won a majority of votes in Snohomish County. Here are the results:

2004

Statewide:

Rob McKenna (R) 52.9 percent

Deborah Senn (D) 43.27 percent

Snohomish County:

McKenna 54.4 percent

Senn 42.2 percent

2008

Statewide:

McKenna 59.5 percent

John Ladenburg (D) 40.5 percent

Snohomish County:

McKenna 61.4 percent

Ladenburg 38.6 percent

Source: Secretary of State