All psychoactive substances should be legalized to be sold to adults as alcohol and nicotine are.

...This was a slog to read. The debate just gets incredibly repetitive after the first round and I read completely through the third before I started skipping large chunks of the same points being made over and over.

It's very simple. Pro has a general argument about why these psychoactive substances should be legalized and provides reasoning that's largely based on free access being a general good. That's fine, albeit it remains poorly weighed against safety concerns in the end. I've judged a debate by Pro before and I still don't buy the "what about this other dangerous thing that's allowed right now?" argument. It's an argument that utilizes existing hypocrisy in the legal structure as a basis for legalizing something, which may make sense on a level of fairness, but since fairness is never weighed as an impact, it feels a bit empty.

That being said, none of this matters. Con never argues against any of it beyond saying that safety matters more, so fine, let's talk about safety.

Con's sole argument against the resolution is that cocaine is bad. The entirety of his reasoning for this comes in R1, where he says "it brings about cardiovascular issues which escalate to stroke and brain seizures." and cites an article by Mark Shrayber. First off, usually a good idea to provide a link to the article so that your opponent and your audience can read your evidence, especially since this was your only source. Second, just because you say something about health harms that can result from drug usage doesn't mean that you've weighed your argument. Stroke and brain seizures are terrible, but how often do they happen and at what dosages? The article goes into some detail on this, but Con relies entirely on voters and his opponent to read into his source. You can't weigh these points just by claiming them over and over again. You can't get any extra weight just by saying that there's a safety risk that can be triggered on first use, one that could even result in death. That's a big impact, but it matters a lot more when you give numbers, and Con cannot rely on the article to provide those without quoting them in his argument.

More importantly, though, that argument has multiple counters from Pro. I see several places where he talks about mixing drugs and the effect those mixed drugs have on the body. Even if I buy Con's argument wholesale that pure cocaine presents a substantial risk, Pro tells me that the mixing of ingredients that happens on the black market results in deadlier drugs. So, at minimum, there's a boost to safety of cocaine use among those who are already using it on the illegal market, and since I don't know if or how much cocaine usage would expand post-legalization, that point stands pretty strong. But let's say I'm not entirely sure how that safety balances with the safety of pure cocaine usage. Pro also has this benefit for every other drug on his list, and with no apparent harms resulting from their usage in their pure forms (Con builds his entire case on cocaine), Pro is, essentially, achieving absolute safety for every drug on the market aside from cocaine. That's a huge safety impact, and the only response I see to all this is that the government currently makes these drugs illegal, so they must be dangerous. That's a broad appeal to authority that isn't based on any evidence. It's a weak response to the kind of biochemical information that Pro provides, and it doesn't suffice.

So, frankly, it's pretty obvious Pro is winning this on the safety level, but also beyond it since he's the only one arguing issues of freedom and fairness, despite those likely being smaller impacts overall. Pro, don't let the debate get dragged out like this in the future. You basically had this locked up by the end of R2 and you just have to stay focused on the key issues. Letting Con distract you and get under your skin could only hurt your position.