States will have referendum on leaving the union, The majority wins, get it. You don't like it pack your sh!t and git. No civil war is desired or necessary.
Let’s use Illinois as an example.
The state voted 40% for Trump.
80% of the state’s counties (mostly south of Chicago) are red.
If the IL legislate & governor decided to leave the union, would the 40% of residents (who control 80% of the land area) agree to leave?
Or would they succeed from the state of Illinois? Would they declare themselves a new state (called South Illinois) and apply for statehood in the Union?
How would the legislature & governor stop them? The state has no army.
The Illinois government doesn’t have enough firepower to force South Illinois to remain part of the state.
State troopers and police are likely to split along red/blue lines too. So threats is all they could make.
In summary, the most likely scenario if Illinois left the union is:
1. Illinois leaves the union.
2. Red Illinois counties refuse to go along and band together to succeed from the state of Illinois. Forming a new political unit: South Illinois.
3. Illinois’ government orders state police to secure the red counties. The police who are residents of the red counties refuse the order and switch sides.
4. There is violence between the blue & red security forces. Neither side has the firepower to force a victory.
5. Eventually, a truce is called and a treaty is signed recognizing the red counties as a separate political entity: South Illinois.
6. South Illinois applies to the Union for admittance as a state.
None of this involves anyone outside the boundaries of the current state of Illinois. No national civil war, but state level civil war.
Yeah, except there is no peaceful, lawful method to leave the union; that was decided over a century and a half ago. States can hold a referendum, but the referendum would be meaningless as far as the federal government is concerned.
The only method to leave the union is to be prepared to have a shooting war with the US government and win it.