The acts of violent and inflammatory members working for the government characterize the groups as violent and erase public sympathy for their causes. The groups can then be suppressed or exterminated with little public outcry. It is naive to think it can't happen to us. A single politician assassinated or a building blown up by someone claiming to represent the Libertarian Party would cost us many years of progress. The pledge undermines this tactic.
Libertarians often encounter the common belief that all radical political groups are violent.
Normal and natural fear of violence thus becomes fear of us. Hundreds of times I have had to emphasize the nonviolence of libertarianism to counter this fear. The pledge is clear proof of our commitment to nonviolence. In all my years talking and listening libertarianism I don't remember anyone who wanted to be a dues paying member but refused because of the pledge. Arguments for abolishing the pledge seem to assume that there are tens of thousands of such people.