The answer lies with Muslims themselves. Specifically, it means that Muslim religious leaders around the world must announce that any Muslim who deliberately targets non-combatants for death goes to hell.
I arrive at this answer based on something that I have long believed about Pope Pius XII and the Holocaust.
I readily acknowledge that the situations are not the same. The Jews of Europe were not annihilated by Catholics in the name of Catholicism; whereas the Christians, Muslims and Jews who are massacred by Islamic terrorists are murdered by Muslims in the name of Islam.
I also readily acknowledge that many of the attacks on Pope Pius XII for his alleged inaction and even collaboration with the Nazis during the Holocaust are animated by individuals who hate Western religion generally or hate the Catholic Church specifically. Pius XII was not "Hitler's Pope," as one best-selling book on Pius XII is titled.
Moreover, Pius XII lived in Italy during World War II, in a fascist dictatorship that began as Hitler's ally and ended up being the target of Nazi atrocities. This was not the case with President Franklin D. Roosevelt, for example, who lived in the safety of a free country six-thousand miles away from Germany, did nothing to save the Jews of Europe, and even sent a boatload of Jewish refugees from Hitler back to Europe. Yet the critics of Pius are silent about Roosevelt.
Nevertheless, Pius could have done more to at least slow down the Holocaust. And I say this recognizing that Italy's Catholic clergy saved many Jews, and that Pius, to his credit, had to be aware of this. What he could have and should have done was to announce that any Catholic -- and any Christian for that matter -- who in any way helps in the murder of innocent Jews is committing a mortal sin and will not attain salvation. In other words, he or she will go to hell.
This would have had no impact on the many Germans and other Europeans who had no belief in God or religion; but it would have had an impact on many who did.
I believe the same thing regarding Muslim terror. Muslim leaders -- specifically, every imam in the world who is not a supporter of terror, the leaders of the most important Sunni institutions, such as the Al-Azhar Mosque and University in Cairo, and religious leaders in Saudi Arabia and the in Gulf states -- must announce that any Muslim who participates in any deliberate attack on civilians goes to hell.
This must be announced as clearly and as repeatedly as, for example, Muslim condemnations of Israel.
Just as the promise of immediate entrance into paradise animates many Muslim terrorists, the promise of immediate hell would dissuade many Muslims from committing acts of terrorism. Just as the promise of 72 virgins animates many Muslim terrorists, the promise of hell would dissuade many Muslims from terrorism.
Whenever non-Muslims ask Muslim organizations about Muslim terrorism, these organizations trot out the various anti-terrorism statements they have issued. But these are largely useless because: a) they are usually issued by Western Muslim organizations; b) even when they are issued by Middle Eastern Muslims, they almost always include condemnation of "state terrorism," which is Muslim-speak for condemnation of any use of force by Israel; and c) these statements usually also condemn non-Muslim terror, as if Christian or Jewish or Buddhist terrorism is as great a threat to humanity as is Muslim terrorism.
Therefore the statements that need to be made by every Muslim teacher, school, mosque and organization that does not support Muslim terror must be unequivocal. They need to state that any Muslim who targets (SET ITAL) any (END ITAL) civilian for death -- whether that civilian is Muslim, Christian, Jewish, Hindu or of no religion -- goes to hell.
In addition, there need to be large Muslim demonstrations against Muslim terrorism. I understand that Muslim clerics who would organize such demonstrations in the Muslim world might be risking their lives. But what about Muslims in America and Europe?
There have been huge Muslim demonstrations against cartoons depicting Muhammad and any other perceived "insult" against Islam. But I am unaware of a single demonstration of Muslims against Muslim terror directed at non-Muslims.
And if morality doesn't persuade Muslim leaders to issue such a statement and organize such demonstrations, perhaps self-interest will. To just about everyone in the world outside of academia and the media, Islam is not looking good. Muslim leaders should be aware that with Muslims burning Christian churches and Christian bodies in Pakistan, Iraq, Nigeria, Egypt and elsewhere, and the regular massacring of innocents by Muslim terror groups, the protestations by Muslim spokesmen that "Islam is religion of peace" are beginning to wear thin. For a religion that seeks converts, this is not a positive development.
On the other hand, perhaps not that many Muslim religious leaders do believe that Muslim terrorists are going to hell.