There are two fundamental prerequisites for the validity of any action; particularly any sort of intervention.
First, you have to establish that you have the right to do it, and second, you have to establish that you have the power or ability to do it successfully.
If you have the power to do something, but do not have the right to do it, then, of course, it is invalid, and I think most of us recognise that. We experience often enough the abuse of power to know this.
But I think we overlook the invalidity of actions undertaken when we have the right to do them, but lack the ability or power to actually carry them out properly or effectively or successfully. The consequences of such actions can be just as, if not more devastating than actions done through the abuse of power.
Related to this is another area in which I think there is a good deal of confusion. This has to do with an action being justified and also being moral. These are not the same things; being one or the other does not automatically make something both.