State Sen. David Ige, a soft-spoken, deliberative engineer, has quietly navigated politics at the state Capitol for nearly three decades.

His faction in the Senate is known as the Chess Club — policy wonks and liberal idealists who have stuck together while other factions frayed. So Ige’s announcement Tuesday that he would challenge Gov. Neil Abercrombie in the Demo­cratic primary next year is an unusually risky move for a lawmaker respected for his judgment.

Ige will not be able to run for his Senate seat when it is up for election in 2014.

"I think the real fundamental difference is the way that I approach issues and problems and challenges that our community faces," Ige, 56, said in an interview in his Aiea home with his wife, Dawn, and three children nearby for support. "I really do believe in engaging the community as part of the solution, and we’ll be working to that end."

Ige would not specifically criticize Abercrombie’s performance, but said, "I’ve heard over and over from people that Hawaii deserves better. We can do better. And I really hope to be part of that change."

No governor since statehood has lost re-election in a primary. Even credible challengers — Lt. Gov. Jean King against Gov. George Ari­yo­shi in 1982, Lt. Gov. Tom Gill against Gov. John Burns in 1970 — struggled.

Abercrombie raised more than $2 million for his re-election and had $1.3 million in cash on hand through the end of last year. Ige had $73,980 in his Senate account.

Abercrombie, whose job approval ratings have remained under 50 percent for the past few years, dodged a threat when U.S. Rep. Colleen Hana­busa chose to challenge U.S. Sen. Brian Schatz in the Demo­cratic primary for Senate rather than run for governor.

But political analysts say it will take more than the governor’s tepid approval ratings to leave him vulnerable in a primary, given the state’s economic recovery.

Ige lacks name recognition outside of his Senate district in Aiea and Pearl City, has never raised the kind of money necessary to be competitive in a statewide campaign and does not have sharp ideological differences with the governor that could splinter the party.

As a veteran legislator, Ige will have difficulty exploiting what some critics see as Abercrombie’s weakness: that he still has the mindset of a legislator, not a chief executive.

But Ige, who has a substantive policy record and is chairman of the Senate Ways and Means Committee, could be a viable alternative for those in the labor and environmental wings of the party, who are the most disappointed in Abercrombie. Ige could also appeal to some of the establishment Demo­crats who have never been entirely comfortable with the voluble and often impulsive governor.

"I’m an engineer by profession," Ige said. "I’m very systemic in how I approach public service. I try and look at issues and try to understand what the root causes might be."

Ige said he has "learned that legislating policy is only half the challenge. Really the best benefit for the community is how it’s executed."

Ige, who was appointed by Ari­yo­shi to the state House in 1985, was elected to the House in 1986 and was elected to the Senate in 1994. He has been a leader at the Legislature on auto insurance reform, education, health, technology and fiscal management. He was among the senators willing to consider an increase in the general excise tax to help balance the state budget during the recent recession. He fought against Abercrombie’s proposal for a pension tax.

Ige helped guide legislation during this year’s session that for the first time will commit the state and counties to a payment schedule to address the $16 billion unfunded liability in the public-worker health care fund.

As the Senate’s lead budget negotiator, Ige has tried to avoid late-night brinkmanship with the House but has also been willing to enforce Senate positions at the expense of related bills or internal deadlines.

Lt. Gov. Shan Tsu­tsui, who formed a coalition with Ige when he became Senate president in 2010, called Ige a "true friend and trusted colleague" but said he will continue to support Abercrombie.

"Hissupport and leadership as the Ways and Means Committee chair helped the Senate to navigate through trying economic times through the pursuit of a sound financial plan and fiscal responsibility," Tsu­tsui said in an email. "Although his absence will be a tremendous loss for the Senate, I wish him well in his future pursuits. I continue to support the governor, his initiatives and his vision for a better Hawaii."

William Kaneko, Abercrombie’s campaign manager, said primary voters will have a choice. "Voters will have an opportunity to hear and evaluate both candidates’ respective legislative and executive experiences, track records and philosophies. Elections are all about choices. That is the demo­cratic process, and voters will have a chance to engage with the candidates on critical issues that face all of us," he said in a statement.