After reading about Koza’s plan I did some checking. State compacts are indeed enforceable, and they supersede state law. They can be enforced by the state’s own courts, or the federal courts. There are apparently many precedents. So California would have to lump it. There might be a plan in the compact for amendment or dissolution, and they could use that.

I don’t think the elections are close by sheer chance, in fact I think elections are more national than “all politics is local” suggests.

In a national election, you would keep your personal appearances more to the dense areas, and aim as always for places with lots of undecided voters. Media buys tend to be priced as CPM in traditional media, so the cost of that is similar.

Yes, they can tell the difference. National fraud means national conspiracy. (Voting machine hacking being the exception, which is why we need paper trails.) National conspiracy means way too many conspirators to keep it secret.