Would this lead to softer drug laws in general? Or at least some kind of vetting process to sign off on recreational drugs, like a version of the FDA? Obviously a few legacy drugs grandfather their way through, but maybe new things like LSD and MDMA pass muster.
Either way, prison populations are going to be just over half what we have now, and the black market will be some degree less, with all the knock-on effects that might have.
Perhaps the prohibition we got would now be a general prohibition on every recreational drug, specifically mentioning some of the common ones from morphine down though marijuana and down to alcohol and nicotine. So when this is repealed, the backlash against such measures now sticks to all drugs, not just alcohol. This would make any future attempt to ban anything mean instantly conjuring up memories of the prohibition era, by then immortalised and dramatised in film. Just as suggesting a return to alcohol prohibition is seen as an issue of personal liberty rather than public morality or health, so too would all drugs ITTL.
And if, as others have noted, this timeline has America versus the commies, well, since they'd likely have strict restrictions on recreational drugs as they did in OTL. So it would be another chip in the liberty pot, a propaganda point that shows how much freer we are than they.