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Rubio: The second thing you can't vet -- you can vet what people have done in the past. You can't vet what people might do in the future. There's another dynamic at play here, and that is you could allow someone into our country who has no history of radicalization, perhaps they even have worked with you in the past, but they are susceptible to radicalization once they enter the United States because they don't assimilate well, because they fall victim to some of this online propaganda and efforts to radicalize people, and two or three years later, you find that they have radicalized.