Who is being threatened with incarceration besides people who have already broken our existing laws? Per se laws don't threaten a new class of people, but only make it easier to prosecute people who have already committed DUID according to our law. The devil's in the details with this law - if it gives police the right to stop and demand blood from anyone they wish on the flimsiest pretext, it's bad. If it allows police and prosecutors another evidential tool with which to convict high drivers, it's good. How about this: only allow police to test people already charged and jailed for other traffic crimes? There's a lot of restrictions we can place on law enforcement's ability to use this, and we should. I don't mean to straw man you, but I gather your objections to per se laws are part of the broader libertarian objection to DUI laws and I think they are somewhat out of the scope of the conversation - we're never going to agree on DUI laws if you believe people should be able to drive as high or drunk as they please so long as they don't show impairment or damage property.