There seems to be sufficient historical evidence to say that dismantling the government leads to increased crime. That isn't a bizarre notion; one of the leading services which governments provide is the suppression of crime. If no functioning government exists, it would not be surprising to find that this suppression of crime is not being performed.
The historical evidence would come from cases of wars, revolutions, and natural disasters. This essay is not the place (and my commitment is not sufficient) to examine the facts with the minuteness they deserve; I leave that as an exercise for the reader. What I believe such an examination will show is that during interregnums, at the ends of devastating wars, after urban conflagrations or hurricances, there is a period of increased theft, property destruction, and often assault and social conflict.
Assuming that I am right in this -- of course I am right in this -- a military invasion of another nation which results in the destruction of that nation's government will inevitably result in criminal activity. In the case of a war, there is the added problem of leftover partisans. People who supported the losing cause have the opportunity to utilize the breakdown of government as a way of continuing the struggle. In other words, they may use lawlessness as a cover for continuing the war. This is why reestablishing civil authority is a military concern in addition to being a moral imperative.
Now there is a report from Bob Woodward suggesting (although without quite telling us) that as a substitute for effective government in Iraq, the United States has instituted a policy of assassination.
I feel certain that war is bad and murder is worse. Why faceless killing should be less evil than targetted killing is not something I would like to be asked to explain; it may be that there is no distinction at all, but I am loath to tar every soldier with the same degree of guilt as the urban hoodlum or the Nazi Gestapo agent.
There are some who posit that because assassination is given by some sort of official sanction, it is not murder, properly understood. It is, in this view, merely an extension of justifiable warfare. (One needs to work out the concept of a just war in order to make that case persuasively, and any war that is not justified cannot be extended to encompass a concept of righteous assassination.) If, however, even a justifiable war has come to the point where the victorious army is occupying the entire territory of the enemy, such an argument begins to ring quite hollow.
The goal at such a time should be to establish legitimate civil authority and to bring an end to criminal activity in the occupied territory. Failing that, is it reasonable to offer assassination as a substitute?
Perhaps, if one accepts the premise that even a government of criminals is better than no government whatsoever. There is certainly an argument to be made along those lines and I think there is adequate anecdotal evidence from the aftermath of most modern wars to weave a persuasive story along that line. But how does such an argument avoid hypocrisy in the case where the war was originally undertaken to depose a functioning but criminal government?