I thought (as much as I hated the measure) that this might violate the constitution as amended by Measure 36 in 2004. However, I went back and read the text and there appears to be a loophole for civil unions.
It is the policy of Oregon, and its political subdivisions, that only a marriage between one man and one woman shall be valid or legally recognized as a marriage.
By specifying "as a marriage" there is a narrow door opened for civil unions. In a Democratic legislature I expect this will at least get a chance on the floor. I dont know if the votes exist to pass it, but at least this will get an opportunity to be debated. This would be a great positive step towards gender equality in Oregon. Kulongoski deserves a lot of praise for his willingness to move forward on this. Other States that have done this have been forced to by the courts, Vermont, New Jersey, and even Massachussetts with their more sweeping reform. Kulongoski is acting out of sheer political will and desire for equality, this goes above and beyond what other States have done if we can pass it, because other States have been forced to action by the courts.