We got the world though the Cold War. We don't owe anybody a thing.
So we'll let the Muslims throw the Jews into the sea and take over Africa; sit back and let the ChiComms take Taiwan and for good measure, the Philippines; let a nuclear war begin between Japan and the Norks; and let Putin have the old USSR territories back. Then, he and the Caliphate can start to carve apart what's left of Western Europe. England's practically halfway towards bowing to Mecca as it is.
Who cares, right? Not our problem! the USA can just sit back and let the world go by. Oh wait, who's that knocking at our door?
Islam is not a monolith. Even Sunni Islam is bitterly divided against itself. Removing the meddling American presence in their lands, another Cold War relic, they are less likely to join forces against us than are the Catholics and Protestants in Northern Ireland.
The current "leadership" will welcome them in.