A reader dissents from part of this post:
Prohibitionists love to trot out the stale old "this isn't the harmless marijuana you remember from your youth" chestnut. Two points: 1) if the marijuana from their youths was harmless (and I tend to agree it was), then why was it illegal back then? 2) to the extent that marijuana is more potent today than, say, thirty or forty years ago, that means that less of it needs to be ingested to produce the same effect, which, if the method of ingestion is smoking means that less byproduct needs to be inhaled in order to administer the same amount of THC. In plain English, people back in the day smoked until they were stoned, and they still do so today - the only difference is that these days they don't need to smoke as much...
Of course, some might claim that people today will simply continue to smoke until they reach altogether unacceptable levels of pleasure (since smoking to the point of toxicity is physically impossible), but some basic economics help out on that point: in addition to being more potent, today's "super potent" marijuana is also much, much more expensive, even adjusted for inflation, than the marijuana of decades past.
The point is, people who attempt to change the debate by claiming that marijuana is somehow "not the same drug" as it used to be are basically just blowing smoke.