What happened

Wednesday night, Kamala Harris promised in the vice presidential debate that if elected, her and Joe Biden's administration "will decriminalize marijuana ... and we will expunge the records of those who have been convicted of marijuana."

Shares of nearly every stock even vaguely related to pot jumped higher the next day. Tilray (TLRY) was a particular outperformer, rising by 18%, while Cronos Group (CRON -3.73%) advanced 10%, and HEXO (HEXO) increased 8%.

Gavel with marijuana atop an American flag.

Image source: Getty Images.

So what

While the potential vice president's quote is very encouraging for marijuana stock aficionados, we should note that Harris said "decriminalize" and not "legalize." There's a sharp distinction between the two. Legal goods can nearly always be bought and sold at will; that isn't necessarily the case with decriminalized products.

The careful choice of word shows that even relatively progressive (would-be) top federal officials remain skittish about full, nationwide legalization. Rather, we can expect that gradual thawing will continue to come from the states rather than the Feds; next month, no less than five states will vote on sanctioning marijuana for medical and/or recreational use.

Now what

Meanwhile, let's keep in mind that even in 100% legalized Canada -- where Cronos, Tilray, and HEXO are all based -- the cannabis business has some tough challenges (supply issues, thriving black market competition, etc.). It's no wonder these companies frequently post losses. U.S. "decriminalization" isn't the magic wand that will wave all, or even any, of their problems away.