If the effectiveness is high enough, then for some people it could be as, or more, important. To create a overly ideal example as a counterpoint:

There is a WMD of some sort hidden in a major city center. We have captured and are 100% sure that the head people who did the planning and planting of the WMD are in our custody. We have a morally reprehensible, but 100% effective torture method.

1. It is guaranteed that these people know the exact information.

2. Tens of thousands or more will be harmed or killed if it is not disarmed.

3. These people are the reason why the WMD is there to begin with.

In this case I think that taking more drastic measures would be justified.