Well, it's debatable. Take the Battle of Algiers, during the Algerian War of Independence. Several bombs go off every day. French paratroopers take over, kidnap

Well, it's debatable. Take the Battle of Algiers, during the Algerian War of Independence. Several bombs go off every day. French paratroopers take over, kidnap, torture with electricity and most often assassinate a bunch of people (total death toll ~ 3,000 people, a bunch of them innocent). Three months later, the FLN support network in Algiers has ceased to exist. On the other hand, a successful operation by French intelligence led to the FLN torturing a number of their members (based on forged documents), which started to denounce additional members, etc, resulting in the torture and execution of hundreds of loyal FLN members. So, operationally, torture can work (but it's not a sure thing), and it has been part of (AFAIK) the toolkit of all counter-insurgency efforts to this day. The problem is that whoever uses it instantly loses the moral high ground.