One of the bills considered by Colorado's General Assembly this year was a bill concerning the used of deadly force in self-defense by private citizens. Colorado defines deadly physical force as "force, the intended, natural, and probable consequence of which is to produce death, and whic does, in fact, produce death." Section 18-1-906(3)(d), Colorado Revised Statutes. In other words, the debate was over when homicides are justifable when commited by private citizens.
How often does this come up in real life?
According to the FBI, in 2004 there were: 437 justifable homcides by law enforcement (all but three with firearms), and 229 justifiable homicides by private citizens (defined for statistical purposes as "The killing of a felon, during the commission of a felony, by a private citizen"), of which 170 were with firearms, 38 were with knives or cutting instruments, and the remainder of which were by other means. These numbers were not grossly different from those of other recent years.
In Colorado there were 16 justifiable homicides by law enforcement and private citizens combined in 2004. Of these, 12 were committed by law enforcement and 4 by private citizens. All involved firearms. On a per population basis one would expect 10 per year on average, about 7 by law enforcement and 3 by private citizens, but small numbers are inherently prone to dramatic fluxuation from year to year.
Moreover, since this law dealt with only a relatively subtle nuance of existing justifications for self-defense (it applied to cases (1) in which a burglar was entering temporary lodging or a vehicle, (2) in situations other than those where the person acting in self-defense reasonably believed a lesser degree of force was inadequate and had a reasonable grounds to believe and does believe that he or another person is in imminent danger of being killed or of receiving great bodily injury or being kidnapped or raped, (3) where the intruder is killed, (4) where a prosecuter decides to press charges), I suspect that this is something that would actually only come up once every few years.
Thus, while self-defense rules are political hot buttons which indicate a legislators values with regard to the issue, they are more symbolic than they are common events that present a pressing practical problem in the state.