If the NPVIC want to be taken seriously, they need to ignore Democrat majority states, and exclusively lobby the safe conservative states. As long it's marketed as the Never Elect Another Republican Interstate Compact, and sold exclusively to states who think that's a good idea, it paradoxically can only be used to do the exact opposite and elect a Republican who otherwise would have lost. Until the movement gets significant bipartisan support, I see fundamentally four cases:

1. The compact does nothing because the majority threshold isn't reached.
2. The compact does nothing because the Democrat wins all the compact states and the national popular vote and the electoral vote is unchanged.
3. The Democrat candidate wins an electoral majority from the compact states, but loses the popular vote. All the compact states vote for the Republican as the compact requires.
4. Same as 3, but the compact states allege voting irregularities in Idaho and unanimously agree to not count those votes so that the compact states can vote Democrat like they would have done without the compact.