Depending on what your goals are, VX gas can be very effective. There are quite a few situations where thermonuclear devices are very effective. So why don't w

Depending on what your goals are, VX gas can be very effective. There are quite a few situations where thermonuclear devices are very effective. So why don't we use them? Why are certain types of bio/chem/nuclear weaponry considered to be generally banned internationally? Why are they seen in such a poor light the use of e.g. sarin gas by a country can create a multi-national scandal with sanctions, UN observers, and even military threats? My point, which you seem to have missed, is that that effectiveness for intelligence is not the question that should be asked, as it ignores the rest of the effects that happen when you torture (or use nuclear weapons, or VX, ...). Reputation matters. PR matters. In a conflict, these concepts are especially important because escalation matters. Bringing out a gun in a knife fight might win you the current battle, but it practically guarantees that the next battle will be fought with guns from the start. You should probably look up the history of what we did to the Japanese when they tortured Allied soldiers in WW2. A major goal about not torturing people is that we don't want our current soldiers to have to face similar treatment. Torturing (or otherwise escalating conflicts) increases risk to our soldiers.