From WND:
According to Williams, former CIA Director George Tenet informed President Bush one month after the Sept. 11, 2001, attacks that at least two suitcase nukes had reached al-Qaida operatives in the U.S.
“Each suitcase weighed between 50 and 80 kilograms (approximately 110 to 176 pounds) and contained enough fissionable plutonium and uranium to produce an explosive yield in excess of two kilotons,” wrote Williams. “One suitcase bore the serial number 9999 and the Russian manufacturing date of 1988. The design of the weapons, Tenet told the president, is simple. The plutonium and uranium are kept in separate compartments that are linked to a triggering mechanism that can be activated by a clock or a call from the cell phone.”
According to the author, the news sent Bush “through the roof,” prompting him to order his national security team to give nuclear terrorism priority over every other threat to America.
However, it is worth noting that Bush failed to translate this policy into securing the U.S.-Mexico border through which the nuclear weapons and al-Qaida operatives are believed to have passed with the help of the MS-13 smugglers. He did, however, order the building of underground bunkers away from major metropolitan areas for use by federal government managers following an attack.
I suppose closing the southern border would have been too extreme a step, since that would involve admitting an additional dereliction of duty in defending the country. I hope this isn’t true, but the idea that someone would wait to make one really big bang instead of a series of smaller ones does fit the profile of the 9/11, Madrid and London attacks.