Can I be devils advocate and ask why we'd actually want it to be legalised? It's not healthy in so many ways; lung, throat and tongue cancer; exacerbating mental health conditions; likely causes schizophrenia in those who are predisposed. It, along with smoking, also causes litter on the pavements, and it quite possibly a gateway drug to other far more serious narcotics.
And you all want it legalised so you can get your jollies without breaking the law. OK...
You do understand that you live, then you know, you die, and the only point to life is to enjoy it, so laughing at people who want to "get their jollies" is pretty ridiculous. The point of life is not to work hard 9-5 then die, you have the time you have here, then it's over.
For many millions of people maybe billions of people weed helps them relax, it can alleviate symptoms of stress and anxiety, it can reduce pain, it can reduce or prevent seizures. Lung, throat and tongue cancer from weed? or from smoking it and usually with other substances? Tobacco is dramatically more carcinogenic than weed yet it's legal and it has a mind altering effect, though smaller, so what. Have it in an edible, who is getting lung cancer from eating weed... errm, no one at all?
You have a fundamental misunderstanding of weed itself, and there are many many substances that can have negative mental effects that are legal, that doesn't mean they should be made illegal. Regulating weed, controlling the supply, controlling the quality all mean that one, people are much less likely to get other stuff in with their weed and far less likely to smoke it while younger as over a period of years, maybe many, illegal supply will dry up and simply be not viable for anyone to get into.
Also don't forget that today weed is illegal, so people are putting a LOT of effort into making synthetic drugs that are usually legal for a short period at least simply because they are new and not yet regulated. The synthetic drugs around have a monumentally, several magnitudes higher, chance to kill or cause long term effects in people. If you legalise weed, which is for what it is, an incredibly safe drug, you make the pursuit of illegal alternatives pretty much pointless. Why risk taking a dodgy synthetic drug when you have legal access to weed?
There isn't a single valid argument for not making weed legal because it's everywhere already and used on a massive scale by people of all ages in what is a far far less safe way than if it was legal and regulated. On top of that it would have long term monumental effects on crime, community and culture in general. For instance in the states you have hundreds of thousands of people in jail for insanely minor crimes due to the way drugs are treated(which is nonsensically). 98% of all harm that comes from drugs comes from them being illegal. From a family destroyed because a father is in jail after being caught with 2 joints, to a community with a gang problem, a gang problem funded by drug crime. Addiction, because without regulation and with every transaction a risk, buying more effectively becomes a sensible option, so someone has more around and is more likely to overdose or become dependent.
There is zero downsides to legalising weed and many many many many upsides, quite apart from the fact that those who smoke it enjoy it and are perfectly entitled to enjoy their life in a way that doesn't harm well anyone else but themselves also.
Should it be legalised here, yes. It improves the economy, reduces crime, gives people an alternative to far more destructive things like alcohol which causes far more deaths, far more violence, far more community problems. That america is almost leading the modern fight against stupid drug control is rather hilarious seeing as they started it and aren't a liberal place in general. Effective if the puritanical America, which started the fight against drugs, is quite clearly standing up and saying enough... that other countries and people can't see past the stupid anti drug culture we have is embarrassing. THe war on drugs has millions of victims, profit from illegal drug sales is one of the primary sources of terrorism and crime worldwide. There are large sales because there is HUGE demand. But all these anti drug people act like taking a mind altering drug like weed is awful yet drinking, which has a similar mind altering effect(yet more negative effect in most cases) is totally fine and normal.