PORTLAND, Ore. -

Ballots are due by 8 p.m. in Oregon's primary election.

About half the voters have already cast ballots, meaning new allegations against Republican Senate candidate Monica Wehby are unlikely to shake up the race.

A police report says her ex-husband called police to accuse her of harassing him as they were going through a divorce in 2007.

Also on the ballot, both parties are selecting nominees for governor, though Republican Dennis Richardson and Democratic incumbent John Kitzhaber are facing little opposition in their own parties.

There are 20 contested legislative races, including two close races where grassroots challengers are taking on Republican incumbents.

Nonpartisan local races and measures will be decided in many areas. They include a massive school bond vote in Beaverton and efforts to restrict the cultivation of genetically modified crops in two southern counties.