Ballots are due today in the all-mail special primary in Oregon’s 1st district, and the nominees to replace former Rep. David Wu (D) should be known shortly after 11 p.m. EST, when voting closes.

Rob Cornilles, who came up well short in his challenge to Wu a year ago, is the heavy favorite for the Republican nomination.

The Democratic primary was initially expected to be competitive, but state Sen. Suzanne Bonamici has led the way in money, ads and polling, and it would be a surprise if she didn’t win by a significant margin.

Still, anything can happen in a low-turnout special election, and the two Democrats with any chance of an upset are state Labor Commissioner Brad Avakian and state Rep. Brad Witt.

Democrats are strongly favored to retain this seat, which has been held by only Democrats for the past four decades. The district stretches from downtown Portland through suburban Washington County and out to the coast in the northwestern corner of the state, and it includes high-tech companies such as Intel and the mammoth Nike sportswear headquarters.

But after an upset Republican win two months ago across the country in New York’s 9th district, Democrats are not taking Cornilles’ challenge lightly.

There is an effort among local and national Democrats to paint Cornilles as two-faced, running as more of a moderate than he did against Wu last year.

The state Democratic Party has launched a new website, TheRealRobCornilles.com; Rep. Earl Blumenauer (D-Ore.) is re-airing his TV ad from 1996 to highlight its striking similarity to one Cornilles has on the air; and the Democratic Congressional Campaign Committee attacked Cornilles for accepting campaign contributions from Republican leaders in Congress.

“Cornilles called himself ‘the original tea party candidate’ and would be just another vote for the extreme House Republican agenda that is out of step with Oregon,” DCCC spokeswoman Amber Moon said.

Cornilles said last month in an interview with Roll Call that he recognizes the partisan lean of the district, promises to be representative of it in Congress and sees this election as a “do-over” for the district after re-electing a party-line voter.

“If people expect me to be the Republican version of David Wu, they’re going to be disappointed,” he said last month. “I am promising to be independent and do what I think is right for my district.”

Cornilles and Bonamici proved to be strong fundraisers in the primary. Unless polling indicates Cornilles has a chance of winning, neither national party is expected to invest significant money here.

Timing is an issue going forward. The nominees will begin the campaign for the Jan. 31 special at the start of the holiday season, when most voters aren’t paying attention to politics — especially Congressional campaigns.

One Democratic insider noted that most voters won’t tune in until the new year, resulting in an abbreviated campaign.

At that point, the race will be overshadowed nationally by the opening month of the Republican presidential nominating process, and the election falls on the same day as the pivotal Florida primary.