Democrats vote for Democrats. Republicans vote for Republicans

Maybe campaigns don't matter much, at least for partisan offices.

(Except Jamie McLeod-Skinner. She brought Walden down from the heights. Her campaign showed that he wasn't invincible.)

Democrats supported Brown

There's all that work, the money raised and spent, all those ads, all the signs, the "elevator speeches" prepared, the policy papers, the carefully thought out messages, the issues, the meetings with supporters, the joint appearances.  

In the general election, in partisan races, Democrats vote for Democrats and Republicans vote for Republicans. Well, duh.

If candidate quality mattered much, or if campaigns mattered, one would expect to see some dispersion in outcomes. There isn't much. 

Jackson County, Oregon, is a good place to gather evidence because the county is mixed and nearly even in partisanship. There are 91,300 voters who are either Democrat or Republican, of which 44,600 are Democrats and 46,700 are Republican, about a 51-49 edge for Republicans countywide.

(I have excluded minor parties in this discussion. They didn't seem to matter much, and they complicate things without good purpose.)

No surprise on the two county commission races: Republican Rick Dyer won with 55% of the vote over Democrat Amy Thuren, counting only the votes for Democrats and Republicans, and Republican Colleen Roberts won with 54% of the vote over Democrat Lanita Witt, counting again only the major party vote.  In both races a libertarian candidate took 2 or 3 percent. Dyer and Roberts ran a bit better than the partisan edge. Their incumbency might explain it.

In the State Senate race between Golden and Gomez, where the District boundaries give Democrats a 13 point edge, 56.5% to 43.5%, Golden won by ten points. In the State House seat won by Kim Wallan there is a Republican edge of 54% to 46%, 8 points, and she won by exactly that percentage.

Republicans supported Buehler

Does anything but party matter?  Maybe a little. Incumbent US Representative Greg Walden got 53% of the Democratic/Republican vote to McLeod-Skinner's 47%, which meant that her campaign made her fully viable head-to-head contender with Walden, so the outcome was within two percent of the countywide partisan split.

Walden was not "weak." Rather the election showed he was just one more standard-issue Republican when he faced a strong campaign from a Democrat. All that seniority and power, all that money spent on his campaign, all that name familiarity built up over two decades in Congress, and the result is that Walden is brought down to the normal votes "owed" any Republican.

Jamie McLeod-Skinner did better than Kate Brown, the Oregon Governor.  Knute Bueher and Greg Walden got almost exactly the same number of votes, about 50,800. McLeod-Skinner got 3,737 more votes than Brown. Brown slightly underperformed, getting only 45% of the Democratic/Republican vote. 

Knute Buehler was widely thought to be an unusually strong candidate, very well funded, with a moderate image, a physician, a Rhodes scholar, young and good looking. The fact that he ran even with Walden and with Colleen Roberts--but 800 votes behind Rick Dyer, the big winner among Republicans in contested races--suggests simply that Knute Buelher got exactly the Republican votes he "deserved."  Buehler wasn't "strong;", Brown was just a bit weak. 

McLeod-Skinner spent a lot of time in Jackson County. She excited people. Her volunteer activity may well have increased the vote for every Democrat in Jackson County. Her campaign mattered because it showed she was viable. Walden, at long last, had a real opponent.

 Kate Brown spent much less time here, but presumably she spent it wisely in more fertile ground.  She carried Multnomah County over 3-to-1, and got a margin of 190,000 votes in that county,  nearly double the amount by which she won statewide. That is where the Democratic voter were. Jackson County didn't hurt her much. 

Take-away: Pundit speculation about Trump turning off Republicans and somehow ruining the Republican brand seems not to have been the case with voters, based on Jackson County evidence.  Republican voters voted Republican. Greg Walden has been an ally of Trump on national issues; Knute Buehler stuck a more independent tone on abortion, immigration,  the Kavanaugh nomination, and generally in his tone. It didn't seem to matter much. Republicans voted for both Walden and Buehler.

Democrats voted for Democrats. Republicans voted for Republicans.