Republican incumbent: Gordon Smith
Democratic candidate: Jeff Merkley
Smith, 56, has represented Oregon in the Senate since 1997. He had previously been a state senator. He is a cousin of Morris and Stewart Udall, whom I had written about in relation to another Udall's candidacy in New Mexico.
Merkley, 51, has been in the state House of Representatives since 1999, and its speaker since 2007.
Polls cited by Real Clear Politics show Smith in the lead. The latest of those polls indicates a 12-point Smith lead.
The Washington Post reported in June that Smith, in a move that's out of synch with his party's national strategy, has included positive comments about Barack Obama in his campaign advertising. Obama made it clear, however, that he supports Merkley.
In 2007, the American Conservative Union gave Smith a rating of 48 on a 100-point scale for his Senate voting record. Only three Republicans (Collins and Snowe of Maine, and Specter of Pennsylvania) were rated less conservative than Smith.
Smith's seat has been in Republican hands since 1967 (Mark Hatfield was his predecessor). However, his senior colleague Ron Wyden is a Democrat.
Smith won reelection in 2002 by a wide margin. Commentators have called him vulnerable this year but, so far, he has a reasonably comfortable poll lead.