Oregon voters are mailing in their ballots today not only to allocate the state's 52 convention delegates but also to pick candidates to take on incumbent Republican Senator Gordon Smith and to replace outgoing Democratic Rep. Darlene Hooley. In both races, candidates are dealing with a hugely expanded universe of voters -- Oregon election officials expect 70% of registered Democrats to cast ballots -- that may change the outcomes.

In the race to beat Smith, State House Speaker Jeff Merkley, initially seen as the odds on favorite to win the primary, has faced a surprisingly strong challenge from Portland attorney and activist Steve Novick. Running to the left, Novick has characterized Merkley as politics as usual, while asserting he can draw the best contrasts with Smith. Polls have showed the two running neck and neck, though with more than 40% of the electorate undecided.

Should Novick win, it will be the first time a candidate handpicked by Democratic Senatorial Campaign Committee chairman Chuck Schumer failed to make it out of a primary. Schumer recruited Merkley, albeit after several other better-known state Democrats refused to enter the race, and while the Democratic Senatorial Campaign Committee hasn't explicitly endorsed or advocated on his behalf, aides have made known that they believe Merkley would have the best chance to beat Smith in November.

In the state's Fifth District, Rep. Darlene Hooley dropped her bid for a new term citing health reasons, and her life couldn't have been made easier by the fact that her seat is a perpetual Republican target. The district, south of Portland stretching from the Cascade Mountains to the coast, voted twice for President Bush, though Hooley has usually won by ten points or more.

Running to replace her, the Democratic Congressional Campaign Committee recruited State Senator Kurt Schrader, though Steve Marks, a former chief of staff to ex-Governor John Kitzhaber, is also running. Schrader has a political base and more money, though Marks has backing from Kitzhaber and former Governor Barbara Roberts. Both candidates jumped in the race late, given Hooley's late exit, in early February. Three other Democrats are also running, though none look like serious threats to Schrader and Marks.

The Republican side of the primary, in which turnout will be significantly lighter, has turned into one of the ugliest contests so far this cycle as late mail drops accused one candidate of paying for an abortion for a former friend. Mike Erickson, a businessman who ran in 2006, denied the story, as asserted in a letter sent to voters who hadn't cast ballots yet paid for by Kevin Mannix, a former state Republican Party chairman and candidate for other offices.

Erickson has name recognition from running in the district two years ago in one of the few seats Republicans thought they might pick up. Mannix, who has run for governor twice and served in the 1990s as a State Senator, has high name recognition as well. And while Erickson has vastly outspent Mannix, who got a late start in the race, the last-minute allegations -- true or not -- could have an impact.

After two competitive primaries in advance of the November elections, the eventual Democratic and Republican nominees are going to receive a lot of attention from their national parties. In such a swing district, in a presidential year, the seat could prove to be one of the tightest in the country.