OLYMPIA — Democrats’ brittle majority in the state Senate crumbled Monday when two conservative members defected and joined Republicans to seize control of the chamber for the 2013 session.

Democratic Sens. Rodney Tom of Medina and Tim Sheldon of Potlatch said uniting with the GOP in a new ruling majority will bring about increased bipartisanship in decisions made in committees and on the Senate floor.

Tom and Republican members of the Majority Coalition Caucus, as they are calling it, insisted they will share power with Democrats and govern from the middle, which is what they believe voters want.

They said the coalition’s goal is to develop a sustainable state budget, fund and reform public schools and increase accountability of government agencies.

“I think it’s exciting,” said Sen.-elect Barbara Bailey, R-Oak Harbor. “I don’t think the people of our state want us to continue to choose sides and argue.”

A key piece of the plan unveiled Monday calls for Republicans to chair six committees, including those dealing with the state budget, education and health care. Democrats will run six committees, while the parties will co-chair three others, including transportation.

“This is the sort of cooperation people are hungry for,” said Senate Republican Leader Mark Schoesler of Ritzville.

Crossing the aisle paid dividends for Tom, who stands to be elected Senate Majority Leader by the caucus when the session begins Jan. 14.

Today there are 26 Democrats and 23 Republicans in the chamber. With Tom and Sheldon, the new coalition will hold a 25-24 advantage.

Democratic senators weren’t surprised by the announcement. Tom and Sheldon had talked openly of forging ties with the Republican caucus.

But Democrats said its formation is a recipe for divisiveness and gridlock. They objected to what they deemed a take-it-or-leave-it approach put forth by the coalition.

Sen. Nick Harper, D-Everett, called it “a power grab disguised as bipartisanship” and won’t yield any more cooperation “than what they criticize they are trying to get away from.”

The result will be gridlock “and a doubling down on D.C.-style politics,” he said. “We don’t want our Washington to operate like the other Washington, where a parliamentary arms race has made Congress dysfunctional and put up roadblocks preventing any meaningful change.”

Sen.-elect Kirk Pearson, R-Monroe, strongly disagreed.

“I think it is a recipe for everybody working together,” he said. “I looked at it as a way that we could show people it is not one-party control but it is two parties working together.”

Gov.-elect Jay Inslee, a Democrat, downplayed the significance of the move in a prepared statement.

“Our goals and the business before us haven’t changed,” he said. “Regardless of the structure in the Senate, I look forward to working with legislators from both parties to move our state forward.”

In the House, where Democrats are comfortably in control, they are taking a wait-and-see attitude. When Republicans pulled off a coup with the aid of Tom and Sheldon last session, negotiations on a budget stalled and drove lawmakers into special session.

“Today’s events certainly have the potential to make reaching consensus even more difficult in an already difficult year,” House Majority Leader Pat Sullivan, D-Covington, said in a statement.

State Rep. Mike Sells, D-Everett, sounded philosophical.

“You deal with the cards that you are dealt with,” he said. “I think (Democratic senators) were under the illusion that they had won the election.”

Many questions remained about what lies ahead. For example, it’s unclear if Tom and Sheldon will continue to attend meetings of the Democratic caucus and if Tom will move into the spacious office of outgoing Senate Majority Leader Lisa Brown, D-Spokane.

And Democrats need to decide if they will accept the coalition offer to lead six committees or work to keep their members in charge of other panels.

One Republican committee chair is Sen. Pam Roach, who was kicked out of her caucus two years ago because of accusations of mistreating staff. She was allowed back in this year during the Republican budget coup last year, but she is still barred from interacting with Senate staff. The committee she would chair is Government Operations.

Mike Hoover, a senior Republican attorney for the Senate, had sued the chamber earlier this year and said he was subjected to a hostile and abusive workplace because of Roach. Under a settlement announced in September, the Senate reaffirmed its sanctions against Roach.

Tom said that would change, and the Senate committee that handles personnel matters would lift sanctions against Roach. He declined to assess how that decision could impact the lawsuit settlement, but he said Roach has vowed to run the committee appropriately.

“She’s going to act in a professional manner,” Tom said. “She has served her two-year period, and I think it’s time to move on.” Hoover, who now works for the House, declined to comment.

The coalition’s plan to remove Sen. Rosemary McAuliffe, D-Bothell, as chairwoman of the Senate education committee isn’t sitting well with the veteran lawmaker, who won re-election last month.

“I am shocked and I am disappointed,” she said. “To take away my chair, that’s a takeover. That’s not a coalition.”

Things could change, she hinted.

“It’s a long ways to Jan. 14 and I think the public will have an opinion,” she said. “I do not believe the public will support this coalition.”

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

The Associated Press contributed to this report.