96 years ago, John McCrae wrote the poem "In Flanders Fields." This poem has never rested easily with me. On one hand, it is obviously proper to honor the lives of the dead. But on the other hand, it seems foolish to pursue a course of action just so as to not "break faith" with those who have died in this cause. If the living do not take up the quarrel, it is an admission that those who have died have died in vain, for a bad cause. It is only natural to feel that this would dishonor their sacrifice.
But to continue sacrificing people to a bad cause dishonors and disrespects the living. And that is the priority. The Dead are beyond our ability to help. We can only remember them. The Living have potential in this world. This should not be squandered pursuing a foolish course of action.
I guess my feeling is that our ethical obligations are for the Future, not to the Past. Sad though it may be, the Dead are of the Past. There is no moral justification in risking the Future by keeping faith with the Past. There is no redemption in pursuing a failed cause.
Here is a link to the Wikipedia page for In Flanders Field.