Presumably, countries go to war for intensely practical reasons. They have goals they wish to carry out, and they feel the costs and risks of war are justified by those goals. On the other hand, in war there is always an enemy, and sometimes other players, too, with goals of their own, so the outcome is never guaranteed. Usually, both sides lose in a war, but one side always loses more than the other.

America's goals in this war are pretty clear, it seeks to punish, and hopefully, dismantle a criminal organization that attacked it, and to do the same to the state which enabled and sheltered that criminal organization. The goals will be met if that organization can no longer repeat its crimes, and if others with similar designs will be deterred by the prospect of such punishment.

But wars also have unforeseen consequences, events tend to cascade out of control, and there are always unanticipated developments. When the original goals are forgotten, or made irrelevant, or when subsequent events introduce new goals into the equation, there may come a time for agonizing reappraisal.

But it should also be remembered that peace can have unforeseen consequences too, and lead to even bigger problems down the line. I'm not sure I know how this situation should be handled, I'm not sure anyone knows for sure. That's why we have leaders and experts. I hope they know what they are doing. After Vietnam and Iraq, I can see they always don't, and the final result is never preordained. We lost the first, and won the second, but we survived South East Asia, the losses from the Middle East are still to be determined.