Can and does the F.B.I. go after people who buy or sell Medical Marijuana?

Since Marijuana is legally against federal constitutional law's to have/sell in the U.S.A

Can an does the FBI go after doctor's and patients who buy sell marijuana and what kind of jail time do they face?

Federal Laws seem to override state laws no matter what laws california passes if the consitution says marijuana is illegal the states must abide, same with stuff like abortion if its legal federally then it can't be banned.

In this case, the courts have determined that federal law has precedence under the Commerce Clause of the U.S. Constitution. This is where things get very strange: Even though someone can grow it for their own medicinal use, it interferes with the interstate trafficking of marijuana, which makes it a federal issue, even though trafficking of marijuana is illegal. The case was Gonzales v. Raich.

And it is the DEA that has jurisdiction, not the FBI.


*EDIT* - Not all federal laws "trump" state laws. As for the abortion issue you referenced, it use to be up to the states to decide until the U.S. Supreme Court interpreted the Constitution to say that banning abortions violated the Due Process clause of the 14th Amendment. And the case I referenced above, they used a case from 1942 (Wickard v. Filburn) to come up with this crazy interpretation of the Constitution's Commerce Clause.

The F.B.I. does not usually involve itself with drug trafficking. That is the responsibility of the D.E.A. or Drug Enforcement Agency

Yes Federal law trumps state laws on Marijuana every time. I believe it would be the DEA not the FBI who would go after such things.

Only if they don't have a license to grow it.