Make it legal so we can send them to jail just for having it in their system.

Not exactly. Legal punishments would be for public intoxication and nuisance, not mere intoxication. I don't want anyone dragged to prison for being high as long as that high person minds his own business, behaves normally in public, and lets other people do the same.

Of course, employers would (and should) continue to demand sobriety on the job, regardless of the legal status of a particular intoxicant.

I hold the Libertarian position on drug use.