Agree with the first part, no way the second part will happen, is there?
What does that leave as a choice?
The extermination of Islam as a religion?
How do you forcibly convert over a billion people without becoming that which you fought to destroy?
The way HAS to be through the spread of moderate Islam, and the philosophies of organizations such as the Islamic Supreme Council of America, and the physical destruction of Islamic extremism and the people who would finance its spread.
Christianity (in the New Testament) promotes peace, and yet extremism and inter-faith struggles have surfaced in the modern world, most notably Ireland. So expect that there will always be extremists, but if the vast majority of the people do not allow themselves to be pulled into the irrationality of killing in the name of God, we can survive this as we survived the spread of communism.
I am the last person in this site that you'd expect to see quoting Pat Buchanan in a positive manner, and yet, it seems that stand in full agreement with him on this issue.
"In the last century, America was threatened by a global communist revolution. Avoiding all-out war, we outlasted it. And we can outlast this Islamist revolution. What we must avoid is a war of faiths, a war of civilizations between Islam and America. And those who propagandize for such a war are the unwitting or willful collaborators of Osama bin Laden."---Pat Buchanan