The Left will not fight a civil war by your rules. They will not assemble in the open to have gun battles with you.
They will throw a firebomb into your house at 3am while you sleep.
They will plant IEDs at conservative gatherings. They will get you fired. They will file anonymous police complaints against you. They will have people smile in your face while getting information about you they can use against you.
They will operate out of your sight as much as they can. That’s how they do things.
Not much of a “Civil War”.
Maybe 4th generation warfare, at best. These sort of tactics are useful when you control the press and the government. They do not work so well when you do not control the press and the government.
The military and police are on the side of the conservatives. In the sort of situation you posit, that is a huge advantage to conservatives. Additionaly, it is getting much, much harder to be able to do those things and not get caught.
The police are on the side of the people who control their paychecks and pensions. If these people tell the police to stand down while Leftists beat the crap out of us, then they will stand down. They HAVE stood down. They might like us, but for most of them, not enough to lose their jobs over it.