National popular vote would very likely kill the two party system.

The coasts ruling argument doesn’t make sense. Candidates spend 85+% of their time in 10 states right now, and sometimes more than 90% of their money. How is this system preferable to a system where one vote in CA is worth what one vote in KS is worth?

We already have a system where 30% of the US population controls the majority of the senate. Therein is the check and balance.

I like that national vote and accept that political leanings may change all over the country, like they have many times. See the Eisenhower electoral map vs the Regan electoral map.