Michael Chertoff's deepest fears: Terrorists entering U.S. from Canada

America's top counterterror official says "more than a dozen" people tied to Al Qaeda, Hezbollah and other extremists have tried to infiltrate the U.S. since the Sept. 11, 2001, attacks. dig more ttp://www.nydailynews.com/news/us_world/2008/02/10/2008-02-10_michael_chertoffs_deepest_fears_terroris.html