Immigrants are attracted to the US of A from day one, and will be until it's ahead of the rest of the world, as a beacon of freedom etc. We are grateful for such immigrants as the furrier Moishe Gershkovitz (father of George Gershwin), Igor Sikorsky (inverntor of the helicopter), Alisa Rosenbaum (Ayn Rand), you can extend the list. We also got Francis Piven, Saul Alinsky, Noam Chomsky as a result of the same immigration. There is no way to separate bad apples from good ones, and if you are on the Dem side, you'd like to get Alinskys only, and no Ayn Rands. There is no way to predict with 100% accuracy whether this new immigrant will become a terrorist, however if he's a Muslim, that probability somehow becomes much greater.