That Oregon taxed the rich does not seem to have affected the unemployment rate last August – Idaho has lower unemployment than Oregon, for example. What did the tax in Oregon accomplish, do you think?
Oregon has a history predating the crisis of an unemployment rate higher than the national average (Idaho is closer to the national average). Unemployment in Oregon, as in most states, is more driven by national economic trends and developments than what happens inside the particular state. What the tax on business and the wealthy (passed by referendum in January 2010) in Oregon accomplished was to NOT respond to the economic crisis and its consequence in higher Oregon unemployment by cutting public employment and cutting public services (as happened dramatically, for example, in California). Since economic crises are times when average people need more, not less, state services and when cutting public jobs would only worsen unemployment, not cure it, Oregon's tax actions had/have the following virtues: (1) they are a humane response to a time of national economic crisis, (2) by preserving basic state services in education, health, etc., they avoid the damaging long-term consequences for the Oregon and national economies of reducing the qualities and hence productivities of Oregonian workers, (3) by enabling state services to continue they also help the mental health of Oregionians - they feel less abandoned by their communities and societies - which also enhances their productivities; this is because supported workers show a sharply reduced level of mental depression, isolation, etc.
In short, Oregon's tax actions were aimed at a better response (in human as well as economic terms) to high unemployment than what other states did. What Oregon, other states, and indeed Washington could and should have done about unemployment was, at the very least, what FDR did in 1934: namely institute a massive program of federal and state direct employment of the unemployed to perform badly needed social services.