Sanders is too liberal to bullshyt about this bruh.
At least he is the one dude right now outwardly endorsing action on it.
Should add, I'm using pander in the most literal definition sense which is appealing to specific interests to get votes. I honestly, believe out of all the candidates to actually do some shyt on this legitimately, Sanders is probably one of the few who I think would actually follow through.
If anything, I would think Trump would be ok with doing this but that is never ever going to happen. I would think with his somewhat liberal social beliefs (regarding gays for example at least) compared to traditional republicans from being from New York, he would be open or propose this at least but he still has to appeal to his ardently conservative base such as the Christians and puritanical types in his party. Based on what I've seen he seemed open to legalization by the states but then later on became more conservative on the matter which seems to be a trend with him which I think is the result of more conservative folks getting in his ear.