There are still a lot of very angry Americans over the election, I don't think it would escalate to a full blown civil war. But unfortunately our country is more divided than it has ever been in my lifetime imo.
I really don't think they could make it on their own. They would have to have some kind of capital (capital meaning money, not a city) to fund their government. NONE of the states in the US are capable of being self sufficient, so they would either have to set up international trading with the US/Mexico/Canada in order to get food and other goods, or they would have to make a lot of changes to their landscape. The US government would be so angry about losing states they would probably put a trading embargo on them lol.