From the NYT's "U.S. Borders Vulnerable, Witnesses Say":

The federal government's efforts to prevent terrorists from smuggling a nuclear weapon into the United States are so poorly managed and reliant on ineffective equipment that the nation remains extremely vulnerable to a catastrophic attack, scientists and a government auditor warned a House committee on Tuesday...

Dirty bombs, crude devices that widely spread low levels of radiation, are relatively easy to detect. But highly enriched uranium, a crucial ingredient in a nuclear bomb, could easily be shielded with less than a quarter-inch of lead, making it "very likely to escape detection by passive radiation monitors" now installed at ports and border stations, Benn Tannenbaum, a physicist and senior program associate at the American Association for the Advancement of Science, testified at Tuesday's hearing...

Nationally, less than a quarter of the radiation detection devices needed to check all goods crossing the borders have been installed, federal officials said. In New York, for example, none of the cargo that moves through the largest ship terminal or goods leaving the port by rail or barge are inspected for radiation, Bethann Rooney, manager of security for the Port Authority of New York and New Jersey, testified...

Members of Congress have also recently questioned a proposal by the Bush administration to spend $227 million in the coming year to create a Domestic Nuclear Detection Office, skeptical that it will do more than add a new layer of bureaucracy.

"I am not too hopeful about this situation," Representative Bill Pascrell Jr., Democrat of New Jersey, said.

Just remember: only George W. Bush can keep America safe.