While I reject any notion that Islam is a religion of peace, remember that the whole battle against Islam is spiritual, not physical. While God in the Old Testament ordered the Israelites to level down sinful cities and burn them but that was only reserved when the cup of wickedness was full and when the nation became so unusually evil. In the New Testament, the Law has been established and fulfilled by our Lord Jesus Christ. While murder, homosexuality, stealing, etc. remains wrong because Old Testament moral law is carried over to the New Testament, Christians are however not commanded to engage in any bloody warfare at all! Ephesians 6:12 says, "For we wrestle not against flesh and blood but against principalities, against the rulers of the darkness of this world, against spiritual wickedness in high places."
Now just a few pointers. Remember that not all Muslims are terrorists and to assume they all are just because of ISIS, MILF, Al Qaida and Abu Sayyaf is the fallacy of division. Some Muslims are decent people worldly-wise but they are just as lost as the Muslim terrorists. Islam in its basic state with or without terrorism is based on a salvation by works. Even if a Muslim may not be a Jihad warrior or some of them condemn what the ISIS is doing, they are still lost people. Islam itself is really a threat to world peace and Islamic terrorism is justified by the Koran (see related articles below). When I think about what the Koran is saying, that what ISIS is doing right now is perfectly justified by the Koran, what Osama bin Ladin did at 9/11 was perfectly justified by the Koran, yes Islam is not peaceful. On the other hand, it does not justify to trigger a bloodbath against Muslims.
So how can Islam be defeated? Preaching the Gospel and the Christian lifestyle is how Islam can be defeated. Also, it's very important also to continue praying for the salvation of Muslims in places of authority like praying for U.S. President Barack Obama is what Christians should do, not pray for him to die and go to Hell. While Islam says, "Seek out your enemies relentlessly.", the Lord Jesus said in Matthew 5:44 saying to love your enemies and pray for those who persecute you. The Apostle Paul quoted Proverbs 25:21 in Romans 12:20 to be kind to ones enemies like if they are hungry, give them food and if they are thirsty, give them drink and it will heap burning coals which may mean as, it baffles the unbeliever to why the person they hate has done kindness to them. They do not expect kindness from the enemy. At the same time, it might convict them by God's grace, to deal with them so they may be saved.
You may want to read "Who Cares" by Jack T. Chick for more understanding.