The National Popular Vote proposal.

Working around the Electoral College -- which is impervious to constitutional amendment -- through state-by-state legislation. I think it's unconstitutional and doubt that its supporters foresee the strange effects it would have. What would presidential campaigns be like if candidates were basically trying to win through the Electoral College, but also had to worry that some big state that they had no shot at winning might mobilize a high turnout and tip the popular vote?