Since it appears from many arguments I've seen that pot actually has no ill or dangerous effects either to the user or any one around them and causes basically zero impairment of judgment or reflexes, shouldn't driving while high be legal? If not, why not?
Cannabis is not universally harmless. It has strong potential for psychological habituation, and causes lung and cognitive impairment with regular use. Some people describe themselves as "addicted" to cannabis and have minor withdrawal symptoms if they stop it after using for a very long time. That said, the physical impacts of cannabis all resolve within less than a month after quitting.
None of this matters though, because nothing that cannabis does to the body is comparable to what alcohol abuse does to the body. The social, health, and economic fallout from alcohol is far greater than any other drug, legal or otherwise. Since cannabis is far less harmful than alcohol, it is the reason why I think it should be legal. I thought I'd clarify that point before addressing your poll.
There should of course be legal penalties for people who drive under the influence of
any mind altering substance. I would broaden this to include legal pharmaceuticals that have psychotropic impacts, such as benzodiazpines, opiates, and other anti-psychotics. If their medication label says "do not operate machinery after taking this drug", then to do otherwise is IMO illegal and should bring equivalent charges to drunk driving. People should simply not be driving if they are not able to be fully cognizant in present reality. Unfortunately, impaired driving law enforcement mainly focuses on alcohol and not the rest. If someone doesn't have alcohol in their blood and they're in an accident, then they were considered "not impaired", despite the act they may be loaded on pharmaceuticals.
The problem with pot is that there isn't yet an efficient means to test for use like there is with a breathalizer test. Cannabis can be detected in the blood stream up to a week after the last use since cannabinoids are fat-soluble molecules, and therefore it's hard to prove when a person last smoked.
I will, however, vote "no" in principle.