If GWB's policy is implemented, we may end up saving Europe from itself. As free societies rise up from the ashes of theocratic states and dictatorships, a change in immigration will inevitably result. If freedom is part of the equation in the future of the ME then fanatisism will be tempered by hope. People stay put if these conditions are met.
I tend to agree with your hopeful assessment, bubman: that such a turn of events is possible and ought to be encouraged.
The "reverse migration" flow of people back to the Middle East is certainly possible as those nations become free, and President Bush's efforts are instrumental in bringing that freedom.
There would still be concerns around water, local economics, population, and the reformation of the Islamic religion. But with freedom wil come pride, and perhaps a strong desire to repatriate.