You're talking about the National Popular Vote Compact, and not describing it correctly. This effort has been underway for decades, and it has been passed by quite a few states; I support it as the only realistic way to circumvent the winner-take-all Electoral College vote allocation, since a constitutional amendment is generally considered impossible.

The compact would not even take affect until enough states have passed it to control the majority of EC votes. Once that happens, the participating states would allocate their EC votes to the nationwide winner of the popular vote—which is how a lot of Americans think their president is elected anyway.

NPV has support among both conservatives and liberals. Around 10 years ago it was very near to the goal, and I haven't checked lately, but I fear the increasing polarization of the political landscape has had more and more states reversing their potential membership.

Nevertheless, while admittedly, imperfect, it still seems like it would be better than what we've got now; all but two states allocate their EC votes as winner-take-all. You can read more about it at nationalpopularvote.com, which has extensive discussion both pro and con.