More fundamentally, NPVIC doesn't actually require an agreement or compact. States just need to pass a law which says: "If greater than [threshold] of states p

More fundamentally, NPVIC doesn't actually require an agreement or compact. States just need to pass a law which says: "If greater than [threshold] of states pass NPVIC-compliant laws, we will select electors based on popular vote of America, rather than on popular vote of [state]." This type of collusion very obviously doesn't meet the threshold under Constitutional terms, and continues to be a republican form of government. I don't see any issues. This sort of collusion is pretty common too. See local COVID19 response state consortia, codes like UCC, professional accreditations, etc. Without that, the US government would be impotent, since there are things which are outside of federal power, but which require coordination across states. If this were banned, the US would collapse.