I hate to say that I don't buy it here, but popular sovereignty (and its close cousin, social contract) is a core belief of liberal democracy. Literally "the will of the people". The people deserve the state they vote for, nothing more, nothing less. If you try to maintain the institutions over the mechanisms that guarantee those institutions, you'll find that those institutions will slip away from you anyway. You risk turning into the very thing you're fighting. As someone who views themselves as more in the center, this is exactly how I see mainstream left politics going right now.
"The concept of popular sovereignty holds simply that in a society organized for political action, the will of the people as a whole is the only right standard of political action"[1]
"The concept of popular sovereignty holds simply that in a society organized for political action, the will of the people as a whole is the only right standard of political action"[1]
[1]:https://books.google.com/books/about/The_Massachusetts_Const...