You don't know what the cartels would do with legalization, so you want to continue to support them?  How crazy is that?  Where's Capone and all the alcohol kingpins?  Oh, that's right, we took away their profits when we ended the first failed prohibition.

The real question that has to be answered by the prohibitionists is:  "What do you think would happen with legalization?"  We know we'd eliminate all the problems of prohibition, so what's that enormous cost that wouldn't make it worthwhile?  People would use drugs?  They do now.  People would abuse more drugs?  Do you know that for sure?  International data tends to indicate otherwise.

And the driving thing is a tired red herring.  Of course, driving while impaired will be illegal as it is now, and if we work on it, we can come up with better measures for that that are safety-based and not political.

I'll answer what happens when pot is legal (although there are many models to choose from).  It will be regulated by the government like alcohol in terms of potency, packaging and age (perhaps decided state by state, perhaps federally).  It could be sold in state stores like alcohol was in many states, or through licensed distributors.  It would be taxed -- enough to fund treatment programs (that work better than incarceration anyway), which would make all the money we save from enforcement available to go to education or middle-class tax cuts.  You'd also be allowed to grow a small amount for your own use, but not to sell it.  Prices and taxes would be kept low enough so that people won't be tempted to go black-market.  Lots of people who don't like to use drugs for various reasons (health, morality, etc.) will continue to not use drugs.  Others who prefer to do so will now have a choice of alcohol or pot.  Assuming some will switch from alcohol to pot -- that will greatly reduce violence in society and also greatly reduce the dangers on the highways (since it's been proved over and over again that alcohol is far more dangerous than marijuana for driving (which ranks just below fatique).

The question legalization people can't answer is what happens once it's legal.   The truth is you don't know.

I can answer that one.

That said, the taxes alone would pay for treatment, the black market would dry up and cops, from municipal to fed, would no longer be corrupted by the insane amounts of $$.

We could have treatment instead of incarceration, secondary crime would fall, and the truth could be told about the very drugs you are railing against, and not confused with the lies equating pot with substances that will kill you.

I thought you knew?

What will happen is that society will disintegrate into a chaotic amoral free for all of drug addicted crazed thieves, rapists and killers.