David Kopel instructs us that it's important to any movement of non-violence that the people involved in the movement have both the right to bear arms and the arms necessary to defend themselves against those opposed to their goals. Taken to its logical extreme, Kopel should be arguing that any group we expect to follow the MLK model of non-violence be sufficiently armed that they are safe and secure in their own homes. I can't see him arguing that, let alone imagine it happening.
Calls for non-violence arise in asymmetric conflicts and, not surprisingly, it's only the side with little to no power that's expected to be non-violent. "If they would lay down their arms and be non-violent, this conflict would quickly come to an end." "Well, if non-violence is the solution, why don't you lay down your arms?" "Don't be ridiculous - we would be giving up everything we've accomplished... they would run roughshod over us...."
Within the context of an independence movement or armed conflict, for non-violence to work you need three basic things:
A significant number of people who are willing to be injured or killed in order to achieve their movement's goals;
Awareness among groups able to effect change that the injuries and killings are occurring; and
A consequent awakening of strong desire by those groups able to effect change to take the political (and perhaps military) steps necessary to effect change.
When the dominant power makes absurd demands (e.g., "Until there's absolutely no violent resistance as defined by us, for an arbitrary period of time also defined by us, we will continue the present course"), it means that they're not serious about changing their approach.
Similarly, when they make demands such as "you must unilaterally disarm, then you must become entirely non-violent, and then we'll consider making concessions", perhaps simultaneously working to exclude or censor the media from the conflict, their primary goal isn't to achieve peace - it's to knock out the second element described above.