Pot is NOT legal in the US -- at least not from Federal Standards -- the law is just not enforced. It is "legal" in many States as far as State law.
Desirous ....
You are absolutely correct on that. That is why when I made my earlier comment, I noted it is legal in about half of the states. However, as you mention, it is still not legal from a federal standpoint and technically the feds take precedence. The last time I heard a debate on the issue, the federal laws still have weed in the same classification as cocaine. But yes, it is a federal law that is simply not enforced.
However, I agree that lawyers for insurance companies would pounce on that in a minute in a courtroom.
Rub a Dub