Al Gore Junior’s highly announced “popular vote” win was 0.51% of the vote, well within the margin of error and it did not include all ballots (it didn’t even have the contested but approved military ballots in Florida).
We could still be recounting the 2000 election if it was strictly the popular vote.
Additionally, Al Gore’s team got some voters to not vote for GW Bush (unclear if they stayed home, left that part of the ballot blank, or voted third party or for Al) because of the election eve “October Surprise” release of news about GW Bush’s decades old DWI arrest.
Everyone agrees that it was a measurable dip in Bush’s vote total (and with 0.51% of the vote, you can take that as evidence Al didn’t have it sewn up).
I am surprised they haven’t proposed something like this before. The last 2 times the “official” popular vote loser won by electoral vote, the Dems lost. They would have to get a few pink or tossup states to join the movement for it to do any good for them. This is a lot easier than amending the Constitution.