It's unconstitutional, for one thing.
You are absolutely right and I have posted on other fora on that issue. I knew instinctively that the compact idea just didn't seem right.
First of all, as I have pointed out, whether it is unconstitutional has not been decided. Some legal experts say that it is constitutional, some say it is not. It may require a court case to validate either position, but the assumption that "its unconstitutional" is false.
Secondly, even if there are questions regarding its constitutionality, the main thing that's needed is just congressional approval. It doesn't seem like such a stretch that if a very popular measure is up for a vote and the Democrats take both the house and senate, that they would be willing to vote in favor.
re: no clear winner....
There would have to be a runoff. People would not like the result.
First of all, there wouldn't necessarily
have to be a runoff... it depends on the wording of the compact.
Secondly, is a runnoff really that bad? Other countries use them with no problem. And who are those "people who would not like the result"? Since no candidate in that scenario had a majority, I suspect a lot of people would welcome the runoff as a chance to get "their guy" into power.
Also the "action" in a presidential campaign would shift from swing states Ohio and Florida to the suburbs of New York City, Los Angeles, San Fransisco, Seattle and Chicago. Why? Because voters in those areas "swing" locally but cannot swing their states. Those areas, in other words are vote-rich but don't dominate their states. Their votes suddenly become important since the popular vote would be determinative.
First of all, I think there are more 'voter rich/swing' areas in the U.S. other than NY/LA/SanFran. Remember, in 2016, even in deeply-conservative Texas, there were many areas that supported Clinton. So, Candidates would have their pick of dozens of cities where they could pick up votes.
Secondly, they wouldn't even necessarily have to campaign in 'swing areas' to make a difference. Even if Trump had no chance of winning urban NY/LA, and Clinton had no chance of losing, it would still make sense to campaign in those areas because, well, every vote would count.
Could be very annoying where I live, 40 km. from New York City.
Strangely enough, so many people complain about how "politicians ignore us", now you're complaining about unwanted attention.