We should everyone that, in the US, jurors are empowered to nullify laws by refusing to convict. Judges won't let you on a jury if you mention your knowledge of this. They might dismiss you from a jury if you try to educate other jurors on this matter. So, it's best to keep your mouth shut when called for jury duty. But, you're completely allowed to refuse to find a defendant guilty. You may not be able to sway 11 other jurors, but all it takes is one juror to know about "jury nullification" to prevent unjust application of a law. You don't have to explain your reasons for being unable to vote guilty. The worst that will happen is it will take longer and end in a hung jury (and retrial). Best case: the other jurors don't want to spend days trying to get you to change your vote: so they vote not guilty too.
All it takes is one person. Anyone who supports legal cannabis should bring up this topic whenever they can. When laws are unenforceable because prosecutors can't obtain a conviction, laws will change.