Koster told backers in an email he will phone Democrat Suzan DelBene Friday to congratulate her on winning their contest for the open seat in the 1st Congressional District seat.
"With more than 50 percent of the votes counted so far, we have not conceded yet, but remain substantially behind," he wrote. "At this point, it would take at least a minor miracle in the final vote tallies for us to come from behind to win."
DelBene was beating Koster by a margin of 53.3 percent to 46.7 percent following the latest tally of votes Thursday. She's led by roughly the same margin since election night and The Associated Press declared her the winner Tuesday.
DelBene also is winning the special election to complete the unfinished term of Democrat Jay Inslee which runs through the end of the year. She is expected to be sworn in next week.
Koster, who has now lost all three of his races for Congress, cited a lack of money as a cause of the defeat. And he blamed state and national Republican leaders for not stepping up with resources to help combat the money spent by DelBene and Democratic Party groups.
"As you know, we stood together and absorbed my opponent's punishing multi-million dollar attack ads; and in the end, we were outspent more than 5 to 1, yet our 'people-powered' grassroots efforts allowed us to stay on our feet and go toe to toe, and to contend for the win right up to the final moments of the campaign," he wrote.
"Sadly, and for reasons untold, neither the National Republican Congressional Committee nor the Washington State Republican Party stepped up to provide us with anything more than token support," he wrote. "To be frank, we were on our own, yet thanks to people such as you, we nearly overcame the odds."
DelBene raised $4.2 million for the entire campaign of which $2.8 million was her own money. She spent $2.3 million of it in the primary and the remainder in October.
In addition, the House Majority PAC and the Democratic Congressional Campaign Committee combined to spend more than $1.5 million attacking Koster. And, in the final days of the campaign, Koster himself earned a lot of unwanted media attention for the way he explained his opposition to abortion in cases of incest and rape.
Koster, a Snohomish County councilman, raised just over $1 million for his entire campaign, not enough to match his opponent's presence on television.
DelBene, who could not be reached for comment Thursday, expressed no regrets Tuesday about putting in own money.
"I think it was important for me to do my part," said the former Microsoft executive. "This was about the voters making a decision about which direction they wanted to head."
Koster expressed grave concern about the future of the nation in his letter. He said he was disappointed with the re-election of President Barack Obama and the passage of ballot measures legalizing marijuana and gay marriage in the state.
"It seems obvious to me that we have swung wildly in the wrong political direction and that we are now at a point where our society WILL suffer the consequences inherent with bad law and liberal representation," he wrote.
Jerry Cornfield: 360-352-8623; firstname.lastname@example.org.
Link to results
More Local News Headlines
Rash of I-5 brush fires were likely arson, State Patrol says 2:41 p.m. The water has a bad taste but itís safe to drink, officials say 12:59 p.m. Two-year, $38.2B state budget passes; shutdown averted Everett police sort it out: 4 argued, then 3 were shot 12:58 p.m. Local fire crews help battle Wenatchee blaze Snohomish County sheriff: Help us solve young coupleís 1987 murders Proposed ferry fares on deck at Whidbey Island hearing Granite Falls seeks grant to replace 81-year-old bridge
Our new comment system is not supported in IE 7. Please upgrade your browser here.