UN is meeting one of the next couple of months to hopefully start to get rid of all that idiocy. Hard to justify the US's position now with 4 states and DC legalizing it and many countries have been waiting some time to get rid of these stupid treaties and the war on drugs that's literally killing some of them as we speak.
Not only is it this week, but we already know that the outcome document is not going to see any real change to the current state of prohibition - the only sign of progress was a number of countries saying they want to explore different approaches and Canada saying they'll be doing this anyway.
I'd say that is real progress. Canada going ahead with it despite the treaty is a big "FUCK YOU" to the treaty, the US, and all the horrible shit the treaty stands for, shit the US forced down the throats of the world like everything else.
It's not a big fuck you to the US given the US already has plenty of places with legal weed and their logic is "we're not technically breaking the UN treaty because it's the states not the federal government allowing weed". US may be responsible for the treaty but they're not exactly its biggest supporter now.
These things are never so simple. If a country pulls this sort of thing too often, then negotiations with other nations (especially the one whose treaty you pulled out of) will necessarily be much less willing to negotiate new treaties with them.
Treaties are more than just trade, they also signify a strong relationship between nations because the nations who negotiate treaties are signalling that they are willing to cooperate in a constructive fashion with that other nation, and that they want to maintain a peaceful relationship with the other nation.
It is far, far better never to sign up to a treaty that is "bad" (normally a power imbalance) than it is to sign up to one, and then pull out of it.
Well hopefully people notice that the narcotics treaties really just damage poorer countries and don't end up "fighting drugs" anyways.
It's sad to see these made up "crimes" of drug selling and money "laundering", as they do suck up budgets, efforts, and lives in third world countries. One might be cubical enough to think e.g. the US loves this as a way to keep, say, Central America, under control.
You can't retroactively have not signed a treaty, though. Your analysis doesn't address the question of "OK, we're in a bad spot, what do we do?", which is the question facing parties to the Convention.
How do they get out of this? I've read that this is a big holdup in US federal drug law reform.