The problem of US democracy cannot be resolved within the current Constitution. I have argued elsewhere that that particular document was designed to create a 'government' which would not and indeed could not interfere or intervene in any meaningful way with the process of the wealthy acquiring more wealth through business. Given that unfettered capitalism is the greatest threat to the wellbeing of the majority of people, the first thing a government must be able to do is restrain its worst excesses. This no US government will be able to do without tossing out the Constitution and starting from scratch.

BTW, the plural of 'referendum' is 'referenda'.