Of course, when in the life-death situation, you're not going to be thinking about these nitty gritty details. More likely you'll be thinking "If I don't stop this, he's going to kill 'my guys' " as the lady calls them in interviews.
And of course, as always, must be stated again that I AM NOT A LAWYER. My thought process below may well be legally naive. But this is how I justify such actions to myself, if God-forbid, I'm ever put into such a scenario and must take such drastic action.
If you want a much better answer, I strongly encourage you to take the Deadly Force Seminar taught by our own Charles Cotton.
As far as justification, the first place I'd look is:
Realize I left off (2) and (3) because those conditions are clearly met. But for (1) I think most people REASONABLY believe it is IMMEDIATELY NECESSARY to stop someone waving a gun toward you or others in order to avoid IMMINENT HARM.Sec. 9.22. NECESSITY. Conduct is justified if: (1) the actor reasonably believes the conduct is immediately necessary to avoid imminent harm;
In this case, shooting the gunman (even in the back) is a clear way to STOP him from committing IMMINENT HARM on the other people.
That is really the crux of any self-defense or defense of others scenario. Was it NECESSARY to take the action you did (shooting someone else) to stop them from committing imminent harm on you or others?
The key words to remember in any justification to use deadly force are:
Reasonable
Immediate
Necessary
Imminent
The next place I'd look for legal justification is
(1) we'll get to below, but (2) ... I think again, as I discussed in NECESSITY above, that it is REASONABLE to believe that shooting the gunman is IMMEDIATELY NECESSARY to protect the other people from IMMINENT HARM.Sec. 9.33. DEFENSE OF THIRD PERSON. A person is justified in using force or deadly force against another to protect a third person if:
(1) under the circumstances as the actor reasonably believes them to be, the actor would be justified under Section 9.31 or 9.32 in using force or deadly force to protect himself against the unlawful force or unlawful deadly force he reasonably believes to be threatening the third person he seeks to protect; and
(2) the actor reasonably believes that his intervention is immediately necessary to protect the third person.
Certainly an argument could be made that the gunman could have been "reasoned with" "talked down" etc. But in my mind, and I think the minds of most honest, hard-working people you'll find in a Texas jury, attempting to reason with a man pointing a gun is too risky if there is an available method to STOP the gunman instead. Obviously, like we saw with the school board chairman, if you have no means of self-defense to STOP the threat, then you must resort to attempting to negotiate with the gunman to spare your life. Negotiating for your life. Think about that for a minute. If given a choice, is it reasonable to expect someone to NEGOTIATE for THEIR OWN LIFE instead of STOPPING the threat to their life? Obviously, some liberals think it is reasonable. But I'd say the majority of a jury in Texas or Florida will think it more reasonable to STOP THE THREAT.
9.33 (1) basically lays out same justification as found in 9.31 and 9.32.
Sec. 9.31. SELF-DEFENSE. (a) Except as provided in Subsection (b), a person is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to protect the actor against the other's use or attempted use of unlawful force. The actor's belief that the force was immediately necessary as described by this subsection is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the force was used:
(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;
(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or
(C) was committing or attempting to commit aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery;
Sec. 9.32. DEADLY FORCE IN DEFENSE OF PERSON. (a) A person is justified in using deadly force against another:
(1) if the actor would be justified in using force against the other under Section 9.31; and
(2) when and to the degree the actor reasonably believes the deadly force is immediately necessary:
(A) to protect the actor against the other's use or attempted use of unlawful deadly force; or
(B) to prevent the other's imminent commission of aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery.
(b) The actor's belief under Subsection (a)(2) that the deadly force was immediately necessary as described by that subdivision is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the deadly force was used:
(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;
(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or
(C) was committing or attempting to commit an offense described by Subsection (a)(2)(B);
To me, the justification in this case can be boiled down simply to STOPPING the gunman from committing one of the "five crimes" specifically listed which give a 9.31 (b)(1)(C) or 9.32 (a)(2)(B). The important element of these five crimes, as Charles pointed out in his seminar, is that they give you a PRESUMED REASONABLENESS if you use force/deadly force to stop them. Basically you don't even have to prove reasonableness because the law says the reasonableness of your action is presumed to stop one of these "five crimes".
I think a case could be made that you were preventing the gunman from committing murder. But I can also see a very good argument that you were preventing the gunman from comitting aggravated kidnapping, see especially PC 20.04 (a)(5) and (a)(6) below.
Sec. 20.04. AGGRAVATED KIDNAPPING. (a) A person commits an offense if he intentionally or knowingly abducts another person with the intent to:
(1) hold him for ransom or reward;
(2) use him as a shield or hostage;
(3) facilitate the commission of a felony or the flight after the attempt or commission of a felony;
(4) inflict bodily injury on him or violate or abuse him sexually;
(5) terrorize him or a third person; or
(6) interfere with the performance of any governmental or political function.
(b) A person commits an offense if the person intentionally or knowingly abducts another person and uses or exhibits a deadly weapon during the commission of the offense.