How many deaths can be linked to marijuana's use?

Only in cases of severe use, combined with an allergy to it, does this occur. And I can count on one finger the number of times this has occured. It was a big news item at the time.

To dissuade the idea, generally from right-wingers, that I am a "hippie" of some kind, I am no longer a pot smoker, not since college (7 years ago). But still, I find it increasingly difficult to justify the prohibition of such a harmless "drug." Yet we continue to lose many of our best and brightest to prescription drugs, tobacco, and alcohol.

Can anyone please provide a reasonable counterpoint to this marijuana's harmlessness?

Even the tar argument doesn't hold up under scrutiny, since the tar in an unfiltered joint is not as carcinogenic, or nearly as addictive, as the tobacco tar. Nor are there any scientifically sound apples-to-apples comparisons sponsored by the US.

I simply don't see a rational argument against marijuana's complete legalization.