Ethics

The question posed, presumes that it is ethical to have standing armies and that it is ethical in any sense to use war as a means to settle political disputes. Without delving into the arguments against war as an ethically justifiable means, the question can be reframed in a way as to render those arguments of little importance. If we had to train our armies, to combat space aliens, then in a very real sense, consequentialist theory holds true and becomes more of a mandate. If faced with the eradication of a species, in this sense, the human species, any means, regardless of how crude or inhumane become justifiable, as the outcome of not doing so, would insure the whole sale destruction of the species. It is in this sense, that one argument of justifiability comes into view If the consequence is the preservation of the species, not just a way of life, then any and all actions must be taken in support of that outcome.
     The ends justify the means, has become an often touted by line however, this is too often used to justify cruel and bazaar behavior. In the question posed is it ethically justifiable to subject solders to simulated torture in order to increase their respective tolerance of torture if captured, can be justifiable only in the sense, if they (or we) were combating non-human enemies. If the enemy is another human army, then the arguments against war and standing armies applies. However, in the case posed above, then any action, which would insure the survival of the species becomes justified including simulated torture.
Consequentialist theory states in part The value of an action derives entirely from the value of its consequence. It is with this idea that the preservation of the human species would warrant most if not all actions. The value of continuing survival,  which for the most part is a human mandate, clearly makes all actions in this light reasonable. Additionally, simulated torture in this case becomes a minor action, when considering the total destruction of the human race speculating for a  moment, I could see far more grievous actions being taken, but still justifiable under this absolutist scenario. It is with this idea, and the situation stated above, that torture becomes justifiable and perhaps necessary when faced with a dire consequences of non-action.  As a concluding note, reframing the question in this sense, renders traditional arguments against war moot though, I could see some arguments coming to light if in fact we as a human species were to go to war with an alien species.