But they do have something in common.
In 2010, they both ran for Congress and lost tight races to an incumbent: Koster fell to Democratic Congressman Rick Larsen, DelBene to Republican Congressman Dave Reichert, and, ironically, they wound up with nearly the exact same vote totals in those setbacks.
Lessons they learned in defeat are shaping their campaigns this time around. While they are the same people talking for the most part about the same issues, they are not doing so in quite the same way.
Koster is modulating the tone and delivery of his message to blunt attacks on his conservative social views as occurred two years ago.
DelBene, a first-time candidate in 2010, beefed up her resume to overcome assertions she lacks experience to serve effectively in the cauldron of congressional politics.
Each is also hoping they've made the right tweaks in their tactics heading into the home stretch of what should be the closest congressional race in the state.
"The issues are not a lot different in 2012 than in 2010," Koster said recently, before walking in the Railroad Days parade in Granite Falls. "Democrats are already doing the same thing they did in 2010 by trying to divert people's attention away from those issues. I think voters are less inclined to have their attention diverted."
DelBene said she gained valuable experience in that loss.
"I know better where people's heads are at," she said after finishing the same parade as Koster. Voters are more concerned about the economy this year, though social issues come up too, she said.
"Many are frustrated Congress is spending too much time talking about taking away the rights of women and not enough focusing on jobs," she said.
New boundaries and a vacancy explain why 11 people at one point were campaigning to become the next representative for Washington's 1st Congressional District.
Democrat Jay Inslee held the seat until resigning 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 place where Republicans could win.
Seven candidates wound up in the primary -- five Democrats, one independent and one Republican -- with the two top vote-getters advancing to November.
Democrats conceded the top spot to Koster because he was the lone GOP hopeful. He proved them right by winning the primary with 44.9 percent, double the total of runner-up DelBene.
The winner of the Nov. 6 election 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.
Two years ago this week, John Koster stood alongside then-Republican National Committee Chairman Michael Steele at a rally in Arlington and declared: "In our lifetime, I don't think we'll face another election as important as this one."
This year's election comes pretty close for him, as well.
"Our country is at a turning point," Koster said a forum in Burlington in September. "We're in trouble. We're facing what some would call financial ruin."
The federal government is too large and spending too much, he said. The deficit is increasing and regulations are multiplying, which impede the private sector's ability to create jobs needed for economic recovery.
Koster wants to reverse course by slimming government, trimming regulations and repealing the federal health care law in hopes of igniting the economy.
It's a similar message to 2010 because, he said, the situation is not a lot different, "it's just worse."
One could argue the fight Koster is waging now is not much different from the one he's waged since his days as a dairy farmer fencing with Snohomish County regulators and in his career in elected office.
Koster, 61, is an Arlington native who married his high school sweetheart, Vicki, four days after turning 19. The couple have four children and nine grandchildren.
This is his third run for Congress and ninth campaign since winning a seat in the state Legislature in 1994.
He served three terms before trying unsuccessfully for Congress in 2000. Months after losing that congressional campaign to Rick Larsen, Koster won a seat on the Snohomish County Council. He's been re-elected twice.
Koster cites his lawmaking at the county and state levels as invaluable experience for breaking free of the partisan gridlock in the U.S. House.
"I was pretty dogmatic," he said of his early days as a state legislator. "The thing I learned … is everybody's got to get something out of this."
His first bill as a state lawmaker was for a study of the higher education needs in Snohomish, Island and Skagit counties. His signature legislation may be the 1996 "two strikes" law locking up violent sex offenders for life.
Koster also helped found and guide a caucus of conservatives that passed the Defense of Marriage Act defining marriage as between a man and a woman. This year state lawmakers replaced DOMA with a law legalizing marriage for same-sex couples.
He opposes abortion and gay marriage. He wants the federal government to do a better job deporting those here illegally. Children who were brought here illegally and grew up in this country should not be allowed into the state's publicly funded colleges until they're legal, he said.
"When they become 18, their first priority should be to become citizens of the United States. You don't have to say no (to them). You can say that a pre-requisite for entry is to be a U.S. citizen," he said.
Koster doesn't hide his socially conservative views and is confident they will not be critical in deciding this race.
Nonetheless, Koster didn't sign the no-new-taxes pledge authored by Grover Norquist, as he did in 2010. He said he opposes tax hikes but is open to closing loopholes and doesn't want to wrangle over the semantics of whether that would make him a violator of the pledge.
He's also changed his stance on a few subjects. For example, he long argued for eliminating the Department of Education. Now he says the department can stay but should operate with a much reduced role.
"I think you have to be pragmatic about what you can do," he explained.
And this year he hasn't filled out as many questionnaires from organizations that support him. Koster said he didn't want the content used to tie his hands in the future or in an attack ad from his opponents.
"I think we were a little more cautious because people were getting pieces of it and using it" against me, he said.
One possible concern for Koster this time is securing votes from moderate Republicans in King County who differ with him on social issues.
Koster rejects the notion that he needs to learn to "speak King County" to win them over.
"I only know one way to tell people the truth and that's just straight up," he said. "No matter whether you're in the north part of the district or the south part of the district, people just want you to speak the truth."
Private-sector career, government ambitions
Suzan DelBene is not the type of person you'd expect to push her way into the middle of a political scuffle. She's mild-mannered and brainy, a person prone to speaking in paragraphs void of hyperbole.
This week she began airing a television ad intended to show her toughness. The commercial opens with a photo of her working as a high school football referee. "It was perfect training for Congress," she says in the ad.
DelBene's readiness to serve is a question she constantly faces. She answers by talking about her life, how when her stepfather lost his job as an airline pilot, her family moved around the country as he searched for steady work. When he didn't find it, they lived off unemployment checks.
She tells how she made it through college with student loans and financial aid, then enjoyed a career that took her to the upper echelons of Microsoft Corp. as a corporate vice president and the ground floors of a handful of start-ups. Her experience in the private sector, she said, gave her a keen perspective on American ingenuity and enterprise.
DelBene, 50, who is married with two college-age children, said the reason she's running now, as in 2010, is to be a voice for the middle class and to ensure future generations enjoy the same opportunities she had.
"People are going through an incredibly difficult time right now. I don't think our government is moving to give them the opportunities" they deserve, she said. "All children should have access to education and living wage jobs. We need to put policies in place to accomplish that."
DelBene is a social liberal, a supporter of abortion rights and gay marriage. She endorses comprehensive immigration reform and legislation allowing children of undocumented immigrants to attend colleges.
While she's certain to highlight that contrast with Koster, she said the economy is the big issue with voters. She said she supports investments in transportation to create jobs and in education to fill the growing number of positions for skilled workers. She also wants to let a tax break for high-wage earners expire at the end of the year -- something Koster does not want to see happen.
"We need to get people back to work and get our fiscal house in order," she said.
DelBene had a steep learning curve to ascend when she made her entrance into politics against Reichert.
It prepared her well for this go-round. She had a stern test in the primary when she battled four other Democrats and fended off attacks from an independent political committee funded by the mother of one of her opponents.
One reason DelBene succeeded is her willingness to tap into her personal wealth and political connections.
She poured $2.3 million of her own money into the effort -- roughly the same amount she spent in the 2010 election. Those dollars enabled her to air far more television ads and send out more mailers than the other candidates. More importantly, she went from being low in the polls to finishing second.
This week, she bought $400,000 of air time for her new commercial. Though DelBene has not said whether she will put more of her money into the race, Democratic and Republican observers -- and Koster -- expect she will very soon.
Meanwhile, after the 2010 race, DelBene bolstered her resume when friend and ally Gov. Chris Gregoire hired her as director of the state Department of Revenue. When DelBene resigned to run for Congress, Gregoire provided one of the first endorsements.
DelBene touts her time as the state's tax collector for giving her a better understanding of how government can assist and frustrate businesses, and how it might do more of the former and less of the latter.
"You've got to know how the real world works," she said. This election "is about moving the country forward. We need to elect people who are focused on getting results, not on rhetoric."
Jerry Cornfield: 360-352-8623; firstname.lastname@example.org.
The candidates at a glance
Suzan DelBene, Democrat
Family: Married, two children
Occupation: Former director of the state Department of Revenue, former Microsoft vice president
Political: Lost to U.S. Rep. Dave Reichert in 2010
John Koster, Republican
Family: Married, four children
Occupation: Snohomish County Councilman through 2013, former dairy owner
Political: Elected 2001, 2005 and 2009 to the council, former state lawmaker, lost to U.S. Rep. Rick Larsen in 2000, 2010
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