A month before voters in Oregon’s 1st district receive their ballots in the all-mail special election, the Democratic Congressional Campaign Committee is spending like it knows something that no one else does.

The DCCC’s willingness to invest more than $1 million for a contest that few from either party believed Republicans had much of a chance to win has left consultants from coast to coast guessing over its motives. Committee spokesmen say the party simply does not want to take any chances in what are routinely unpredictable and odd-timed elections. Oregon Democrats are so far holding firm, basically offering a nothing-to-see-here explanation.

State Sen. Suzanne Bonamici won the Democratic primary convincingly in November and appeared headed for a likely victory against Republican sports franchise consultant Rob Cornilles, who lost to David Wu last year — a strong cycle for Republicans nationwide. But as of Friday, the DCCC had reserved $1,038,105 of TV time through the end of January, including $72,510 in cable, according to a GOP source tracking their buys.

National Republican Congressional Committee operatives say Cornilles is a strong candidate, but the NRCC has no plans to invest in this race.

One distinction of note is that the DCCC has not expended most of that money yet — it has only reserved the time and can withdraw the pledge at any point in the race. GOP strategists said that the DCCC reserving early locks in a cheaper rate and that this move is likely intended to scare off outside groups.

Mark Wiener, a Bonamici consultant, said he suspects the DCCC’s move is “good preventative maintenance” rather than a red alert that often follows million-dollar buys.

“My feeling is that the DCCC’s investment is more of a taking-care-of-business play,” Wiener said. “It’s not that things are much closer than one would expect at this point; it’s just they want to nail in the advantages that [Bonamici] has vis-a-vis Cornilles before [Karl] Rove, the NRCC and others start dumping money in.”

Bonamici’s ability to self-fund, her support from EMILY’s List, her background as a consumer protection attorney at the Federal Trade Commission, her home base of Washington County — the district’s population hub — and the district’s strong Democratic lean added up to what seemed like a shoo-in winner.

Despite the fact that President Barack Obama won the district with 61 percent in 2008, Democrats there were cautious following the party’s September special election loss in New York’s 9th district. That was the seat of former Rep. Anthony Weiner, who, like Wu, resigned amid a scandal.

Democrats also lost the Republican-leaning Nevada 2nd district in September by 20 points. They won a July special to replace retiring Democratic Rep. Jane Harman by only 10 points in California’s 36th district, which Harman regularly carried with more than 60 percent of the vote.

Jake Weigler, who was a consultant for Bonamici’s primary opponent Brad Avakian, said he thinks the DCCC wants to keep Republican groups out and that it sees “an opportunity to define the race and chalk up a big win to start 2012,” when the party is looking to pick up 25 seats and retake the House majority.

“The DCCC sees there’s an opportunity to define him early and hopefully put this race away early so you don’t have national Republicans coming in at the end to make this competitive,” as they did in New York, said Weigler, who now works for the public affairs firm Strategies 360.

The Sunlight Foundation estimated $1.4 million in outside spending in the New York race, with all but $101,000 supporting the Democrat’s candidacy. But outside groups flooded Nevada with ads opposing the Democratic candidate, with $1.6 million in spending from the NRCC, American Crossroads and other outside groups.

Jim Ross, a California-based Democratic consultant who works regularly in Oregon, said the party could be looking beyond the January contest. The district got slightly less Democratic in redistricting, which will go into effect for the regularly scheduled 2012 elections.

“I also think they are doing it in hopes of making this election decisive so they don’t have to worry about it as much in November,” Ross said. “If that is the case, then it is money well-spent.”

Republicans with knowledge of the district are curious about the DCCC’s decision and note that it stayed Democratic even in strong election cycles for the GOP in 1994 and 2010. The 1st, which stretches from downtown Portland to the coast, has been in Democratic hands since 1974.

Republican Molly Bordonaro, a former ambassador to Malta, knows how tough the district is after losing to Wu by just 3 points in 1998, but she believes Cornilles is a Republican who could break through.

“Rob Cornilles is an outstanding candidate, who has a great business background and a solid grasp of the issues,” Bordonaro said. “He’s going to run a fantastic race, and I think he’s the type of candidate that the people in Oregon want representing them in Washington, D.C. So it’s going to be an extremely competitive race that Rob can win.”

Cornilles’ first ad following the primary left out his party ID, part of his strategy for appealing across party lines. The DCCC is hoping to shatter that image with a television ad that went up last week. It features a clip of Cornilles saying on the campaign trail last year that he was the “original tea party candidate.” Cornilles is now campaigning as a moderate businessman.

Ballots will be mailed to voters between Jan. 13 and 17, and ballots are due Jan. 31.