P1. There should be a strong presumption against threatening people with violence — Unless those people are threatening others, or violating their property rights (e.g. Robbers, murderers, rapists).
P2. For all other people, there must be a very strong case for using violence, or the threat of violence, against them before we sanction doing so.
P3. Credible threats of violence against citizens are inherent to taxation.
P4. We don’t have a very strong case for having the state threaten violence against its peaceful subjects.
C. Until such a case is presented, we should treat taxation as unjustified because of the threats of violence inherent to it.
Common Objections to P3
Objections here tend to follow this form:
“I don’t understand how desirable outcome X would obtain without taxation, therefore taxation is necessary to secure this outcome.”
Even if we ignore that this is an appeal to ignorance fallacy (or a special case of denying the precedent), it would still need to be compellingly shown that desirable outcomes X, Y and Z should be given more collective weight than the prima facie undesirability of the mass threats of violence that taxation is predicated on.
Objections in this category are inadequate twice-over. They don’t constitute the very strong case we need.
The Abolition of Slavery Illustrates the Principle
At one time, activists advocated that massive numbers of slaves be freed. This had never happened before on a comparable scale. No one knew for certain what the effect on society would be. Some feared chaos and ruin, and pointed to the apparent economic advantages of using slave labour.
Ultimately, slavery was condemned nonetheless. The moral motivation for abolishing slavery can be framed in terms of the weak argument above: We treat slavery as illegitimate because it entails threatening peaceful people with violence, without a strong justification for that violence.