DelBene was leading Republican John Koster by a comfortable margin in their battle for an open seat in the 1st Congressional District, considered one of the most politically balanced in the country.
"The numbers are very strong. I feel very confident we will be successful," she said.
With DelBene ahead 53.6 percent to 46.4 percent, the Associated Press called the race for her late Tuesday.
She led narrowly in Snohomish County where Koster serves on the County Council, and by 18 points -- 59 percent to 41 percent -- in the King County portion of the district where the largest bloc of voters are located. She also was ahead in Skagit County.
She expressed no regrets about spending so much of her own wealth in this contest.
"I think it was important for me to do my part," she said. "This was about the voters making a decision about which direction they wanted to head.
"We had two very, very different candidates who had two very different ideas on which direction this country should go," she said.
Koster held the advantage in Whatcom County but the number of voters is too few to overcome DelBene's edge in the other counties.
He wasn't ready to concede and spoke optimistically the tide could be turned.
"It's still too early to tell. We did well in Whatcom but not King, which was not a surprise," he said.
His supporters packed in a tent outside Shawn O'Donnell's restaurant in Everett. As Journey's "Don't Stop Believing" played in the background, they eagerly awaited returns and cheered when Koster snagged an early lead only to be quieted as DelBene moved ahead.
"We still have a lot of votes to wait for so we'll see," he said.
Koster and DelBene also are competing for a one-month spell in Congress to complete the unfinished term of former congressman Jay Inslee.
In that race, DelBene holds a seeming insurmountable edge on Koster, 60 percent to 40 percent.
Inslee resigned in March to focus on his race for governor.
By then, the state's redistricting commission had completed its once-a-decade redrawing of boundaries and converted it from a safe haven for a Democrat to a seat a Republicans could capture.
Tuesday's winner will represent an area stretching from DelBene's hometown of Medina through neighboring communities of Kirkland and Redmond and north to the Canadian border.
It passes through towns and farms in east Snohomish, Skagit and Whatcom counties including Monroe, Snohomish, Lake Stevens and tracts outside Arlington where Koster lives.
Fundraising heavily favored DelBene largely because of the big checks she wrote to her campaign.
She raised $4.2 million of which $2.8 million was her own money. She spent $2.3 million of it during the primary where she beat out four other Democrats. By contrast, Koster raised just over $1 million.
On the campaign trail, DelBene and Koster disagreed on a host of issues.
She supported Obamacare while he called for its repeal. Koster said he'd vote to extend all the Bush-era tax cuts while DelBene said the break for high wage earners should expire at the end of the year.
She endorsed keeping Social Security and Medicare as they are. He suggested future enrollees in Social Security be given an option similar to a 401K and those signing up for Medicare be eligible for vouchers to spend on the insurance plan of their choice.
Down the stretch, their exchanges became a bit more personal.
Koster jabbed DelBene for not voting in elections before her first run for Congress and tried to link her with a complaint alleging political favoritism in the state agency she guided last year.
DelBene said Koster "crossed the line" by placing photos of her home on his campaign website and decried his depiction of people receiving government assistance as lazy and slothful.
He ran commercials labeling her a multimillionaire trying to buy a seat in Congress. Her ads deemed his views on social issues as too extreme and she routinely cited his ties to tea party supporters.
Koster, a former state lawmaker, is in his third term on the Snohomish County Council and trying a third time for Congress. He ran in 2000 and 2010, losing both times to 2nd District Democrat Rick Larsen.
DelBene, a former executive with Microsoft Corp., was making her second bid for Congress; she lost to 8th District Republican Dave Reichert in 2010.
Both candidates looked to show they learned lessons from those defeats this time around. DelBene, a first-time candidate in 2010, beefed up her resume to overcome assertions she lacks experience.
She spent 2011 as director of the state Department of Revenue under Gov. Chris Gregoire, who showed up at DelBene's party in Kirkland on Tuesday.
Koster still criticized her as unprepared for Congress as she had never held political office. In the meantime, Koster sought to modulate the tone and delivery of his message to blunt attacks on his conservative social views. He focused on his desire to reduce the size and scope of the federal government and help the private sector create jobs.
Nonetheless DelBene, Democratic political committees and pro-abortion rights groups attacked Koster's opposition to abortion in commercials.
Last week, Koster found himself in the national spotlight when he said on an audiotape at a fund raiser that abortion should not be legal even when it involves "the rape thing."
Jerry Cornfield: 360-352-8623; email@example.com.
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