On the side of America's enemies are the Democrats, who, among other things destructive of America, encourage third world immigration because the immigrants vote overwhelmingly Democrat and keep these people in office. If this trend continues, America will be overwhelmed by these immigrants and the United States will likely fall.
On the other hand, the September 11 Massacre galvanized the American spirit and united Americans as they had not been in decades. It is possible that Americans under seige will unite in a common defense and that this will spur the American economy to unprecedented growth, as World War II did. And furthermore, it may bring the immigrant population into the mainstream, united with the rest of America in the common defense.
This could take the form of Islamic fundamentalism, the Western democracies replaced by Islamic theocracy dominated by the sharia and with the Koran as "constitution".
However, the people of the West, ever inventive, could create a new, secular form of Islam and then export it to existing Islamic theocracies.
Such a secular Islam presumably would outlaw Western practices most offensive to Islam, e.g. sexual promiscuity, and Islamic practices most offensive to the Western mind, e.g. death by stoning, slavery, and the de facto criminalization of rape victims. Presumably it would also include such Western concepts as the seperation of religion and state, constitutional government, freedom of religion and speech, prohibition of cruel and unusual punishment, and respect for human rights.
This secularized Islam would come to resemble the secularized Christianity of the 20th century. Westerners might achieve that which Muslims cannot.
There would be little difference in the hostility between secularized and fundamentalist Islam and the present hostility between Muslims and non-Muslims, but the difference would be significant.
For one thing, it would provide for a "Muslim Middle-Class" forming a buffering spectrum between the fundamentalists and the secularists, and it could lead to the evolution of Islam into the modern world. It could also provide for the survival of Western Civilization under the guise of Islam.
I am not recommending this. I do not recommend it. But it another possible scenario.