Can speech justify violence?

One often hears some variant of the phrase "speech never justifies violence".

Is that true?

Morally, for some people, perhaps.  Legally, not at all.

Imagine the following circumstance:
  A man carrying a baseball bat approaches you.  When he is within a few feet of you, you draw a concealed firearm and shoot him dead.

Was your action legally justified?  Unless the man exhibited behavior that demonstrated an imminent threat to use the bat against you, absolutely not.

Now this:
  A man carrying a baseball bat approaches you.  When he is twenty feet away, he says "I'm going to bash your brains out."  When he is within a few feet of you, you draw a concealed firearm and shoot him dead.

Was your action legally justified?  Damn right.

What's the difference?  His speech.

The essential requirements to justify the use of force in defense of self or others are generally considered three:

• Ability: the physical ability to cause great bodily harm, permanent injury, or death.  A gun, knife, or club certainly qualifies, as would significant disparity of force (the potential attacker being larger, younger, fitter, or a group of people).
• Opportunity: the opportunity to apply that ability.  A person with a club or knife who is 100 yards away has ability, but not opportunity.  Likewise if there were a 20' fence between the attacker and potential victim.
• Jeopardy: behavior which a reasonable person would find imminently threatening.  Brandishing a bat (when not playing a game in which the bat is used) might qualify depending upon circumstances.  Repeated stabbing motions with a knife upon approach might qualify.  A verbal threat to use force against you definitely qualifies.

In addition, the potential victim must be innocent and any threat must be imminent.  A statement that "I'm going to get a gun and shoot you" is clearly not an imminent threat, and the requirement to leave and obtain the ability also demonstrates that the threat is not imminent.  The similar "I'm going to shoot you" from a person wearing a gun in a holster or holding one in their hand is clearly imminent.

In the above two scenarios, ability and opportunity are present via the baseball bat and the proximity of the potential attacker.  Only in the second scenario is the imminent threat present.

The only difference in the scenarios is the speech.

Contrived?  Perhaps.  But also a clear exception to the idea that it's never justified to respond to speech with violence.