I think that would be missing the point. The Pacific Northwest already started turning against the Republicans on their economic and social policies during the Reagan years, and urbanization would only increase Democratic gains later on. If Bush had won Oregon outright in 2000, yeah, I'm sure Republicans would target the area a little more and the margins might be thinner, but it would be negligible. Eventually, the 2000 results would be chalked up to the Nader effect. The state would be abandoned by the GOP and the numbers would resemble ours.
Could Mannix or Rossi have won in this case?