> The supreme court has said (over-simplifying here) that the right to delegate this legislative power to a popular vote is only constitutional when it adheres to 1 person, 1 vote weighting.

> Taking into account votes external to that state likely violates this.

I don't see anything approximating an argument that National Popular Vote violates any rule that has been applied to Presidential elections (“one person, one vote” is a districting rule, which doesn't really apply to elections per se, and arrangements which do not treat all voters in the state equally—such as the 2 for the statewide winner plus one for the winner of each CD method of assigning electors, which more heavily weights votes in Congressional districts with lower turnout in assigning state electors—survive under current law, and NPV doesn't even have that flaw.)

Deciding how to apportion electors falls squarely within the rights of a state legislature. There's no need for proportion of popular vote to correspond to electoral votes.

What the supreme court has said, is that if any decision is delegated to a vote, then that vote must meet constitutional muster.

Using votes cast in another state to determine the results of what is a state election likely violates rights of voters within that state.

And those rights are not wholely the legislature's to delegate away.

It's essentially extrajudicial gerrymandering.

Separately, and coming from another angle- it likely violates the constitution's guarantee of a republican form of government.

> What the supreme court has said, is that if any decision is delegated to a vote, then that vote must meet constitutional muster.

Anything any government in the US does must meet Constitutional muster. I'd like you to cite the specific decision you think indicates that a decision to assign electors based on the national popular vote would not meet such muster.

> Using votes cast in another state to determine the results of what is a state election likely violates rights of voters within that state.

Based on...what? I mean, except that it has survived so far, I can see an argument to the bare Constitution that giving unequal voting power to different voters within the state, which the two to the statewide winner plus one to the winner in each Congressional district method clearly does, violates the 14th Amendment Equal Protection rights of the voters so disadvantaged. But I don't even see a Constitutional argument, much less actual voting rights precedent, that negatively impacts on NPV.

> It's essentially extrajudicial gerrymandering.

Gerrymandering is drawing legislative districts, which is normally “extrajudicial” (since federal districting is expressly a power of state legislatures, and state-level districting is usually also a power of the state legislature, not the judiciary.) And gerrymandering is often legal and in many cases not even subject to federal review. Rucho v. Common Cause, 588 U.S. ___ (2019).

So saying it's “extradjudicial gerrymandering” is all of false, adding meaningless qualifiers to make it sound significant, and not supporting your argument that it is unconstitutional.

> Separately, and coming from another angle- it likely violates the constitution's guarantee of a republican form of government.

How? Based on what argument and applicable precedent?

Under the principle of "1 person, 1 vote", it would also seem impermissible to assign electors in a "winner takes all" way. Indeed, there is a campaign to test the constitutionality of states doing this:

https://www.usatoday.com/story/opinion/2019/09/10/winner-tak...

It is the sovereign State (1 entity) casting its electoral vote, so splitting the vote makes less sense than a single winner. We're not a parliamentary style government.

If a state is one entity, it should have a single vote. Instead, there is a college of electors, and those electors should at least reflect the electoral outcome in the nominal congressional districts that they represent, as in Maine and Nebraska. (I know that's not how elector assignment generally works, but I think it's just as valid an interpretation as your "1 entity" view).

Neither that per-district system, nor my original popular vote proportional system, would require a parliamentary style of government. Indeed, under a parliamentary system, the executive would be chosen by parliament itself and there would be no need for the electoral college or even the presidential vote at all.

The constitution literally says the States shall choose the president.

Not the people.

States are people, my friend.

(Hopefully that's a less controversial statement than Romney's famous line).