State Power and Threats

Some of my libertarians friends will say that whatever the state has the power to do, it is able to do so because it threatens to shoot you. This is too simplistic, and probably false.
So, for example, if the state wants to impose taxes on you, you have to pay them, because if you don't, they will shoot you. This is obviously false. The penalty for not paying taxes is not a shooting squad. I don't actually know what the penalty is exactly, but it's probably some kind of fine or warrant. Now, what happens if you fight the arrest under the warrant? Then you've resisted arrest. And what happens if you violently resist arrest? You will be met with violence. But each of these are considered on their own and merit their own independent punishment. That's why if you were to go to court after all this, you would face different charges, not just the singular charge of not paying taxes. 

Take a similar example of escalating, but independent, punishments. You tell your child to clean their room. Can it be said that if your child doesn't clean their room, you will spank them? Would it be accurate for you to tell your child that? I think not. If your child does not clean their room, you put them in time out. If they don't go to the corner for time out, you take away their video games. If they continue playing, you will take it from them. If they try to stop you, you will spank them. It could even be said that if your child fights you back, you will fight back, even to the point of shooting them if they threaten your life. So, is your command to clean their room only done so because you are threatening them to shoot them? Obviously not. Each punishment is handed down because there was no heeding to the previous command, regardless of what that command was. And so in government, you will be punished proportionately to the different types of crimes (or an act of disobedience) you've committed, not because of the first one.