See this Seattle Post-Intelligencer update, which begins:

Gov. Gary Locke on Thursday used his veto power to create separate party primary elections in the state for the first time in nearly 70 years.
Locke rejected a “Top 2” primary system similar to Louisiana’s primary, in which all candidates appear on the ballot and the top two finishers, regardless of party, advance to the general election.
Instead, he replaced Washington’s popular wide-open blanket primary with a system like that used in Montana, where candidates appear on separate primary ballots, but voters choose which ballot to cast.