So the FBI is putting together an aggressive plan that includes rousting people suspected of supporting violent extremists. Federal lawmen may jail some who have committed minor crimes or immigration violations and question or tail othersif only to let them know the government can find them. These proposals have provoked sharp debate in the FBI. Some agents say such tactics could backfire by alienating Muslims whose help the bureau needs in identifying suspicious people. Agents have been asking law-abiding emigres to report strangers who spout radical rhetoric or who have large sums of money and no jobs; those who rent apartments and vanish for weeks; or people who borrow cell phones and computers to message friends abroad.
Of course, the FBI isn't relying exclusively on tips. Airport security will remain high, and the borders will be closely watched. After all, eight weeks before the Sept. 11 attacks, all the hijackers were already in the U.S. If al-Qaeda operatives are truly about to attack, as the U.S. intelligence community says, then most are probably already hereor about to cross a border.