I wonder how clearly the ban on vote-buying is written into the constitutions and laws of modern democratic countries, and whether, purely theoretically, the US Constitutional Court could forbid the Democratic Party on this basis?
Even if there's a ban on vote buying, it still happens for some reasons. People are being bought when money is already in front of them and they think it's an easy money for which they only have to vote the one who bought them. While I'm not sure if this is possible in the US, those countries that have the electoral system that involves a different type of election that includes all people and not a block voting type, they can easily feed people with this kind of strategy especially in the poor countries.