As in the original thread, I think the only morally responsible thing to do if torture is - or more often,
seems to be - the only option likely to save lives is to authorise the torture and then face the consequences.
In the case of a president, one should order the torture, and make it clear that the individuals who carry out the torture must be volunteers drawn from those trained in such matters.
Immediately the torture has been carried out, whether or not it yielded useful information that saved lives, or useless information that did not, one's last order as president should be to initiate one's own prosecution under anti-torture legislation, then resign.
The due process system of justice can then deal with the breach of due process and assess, with hindsight, whether or not it was warranted. The law remains paramount,
and anyone that can be saved is saved. Everybody wins.

(Except the poor guy who gets tortured, obviously

)
If the justice system views that the actions taken are justified, then it will find one innocent, or at the very least, pass a lenient sentence.
If, on the other hand, it finds that the order resulted in the torture of an innocent (e.g. the subject of mistaken identity, or someone "bad" who did not in fact have the information they were tortured to reveal), due process will pass the necessary verdict of war criminal. Even then, one would retain one's honour - somthing that doesn't happen when illegality is condoned at the top but nobody at the top gets punished when it turns out that innocent people have been the victims of such illegality.
If our leaders - in business as well as in politics - were prepared to put their own lives, liberty, and careers where their mouths are, they would consider these decisions with more care, and the electorate would most likely develop a great deal more respect for them. I certainly would, anyway.