The Trans-Pacific Partnership (TPP) (see also this view of the TPP, among others) would become FEDERAL law, not STATE law, so you should start your research with your Oregon Congressional Delegation. This is not to say you shouldn’t also talk to your Oregon state representatives, who should be conversant on the subject of the TPP anyway, if only because any national trade laws will affect you locally, your business, you as consumer, and all of us (most of us) as taxpayers.
A brief tutorial: