Outgoing U.S. Homeland Security Secretary Michael Chertoff says the fact that U.S. territory has not been attacked since September 11, 2001, is the central accomplishment of his four years in office.  Chertoff credits the policies of U.S. President George Bush with keeping America safe from further attacks.

Michael Chertoff told an audience at Washington's Georgetown University Thursday he is proud of having helped to guard against acts of terrorism.   

"In the dark days immediately following September 11th, when the smoke was still emanating from the smoldering fires underneath the World Trade Center, no one would have predicted that there would have been no successful attack on American soil in the following seven years," he said.

Chertoff says the absence of attacks since 2001 is a direct result of President Bush's anti-terrorism policies.

One of those policies is the U.S.A. Patriot Act, an act of Congress Mr. Bush signed into law in 2001, broadening government powers to conduct surveillance and gather intelligence.  While some provisions of the legislation have been controversial, Chertoff says the Patriot Act has enhanced his agency's ability to protect the country.

"I would not wish on anybody who has the responsibility to protect the American people, and to look into the eyes of people who lost loved ones in terrorist attacks, as have done, I would not wish on them having to put a blindfold back on so they could not adequately assure the public and themselves that everything possible was being done to protect America," he said.

Chertoff, who is the second Homeland Security secretary, says the creation of the cabinet-level department in 2003 was a revolutionary move to coordinate U.S. law enforcement.

"The purpose was not simply to create a new department," he said. "It was to have one place where the overarching mission would be [to] protect all of our air, sea and land against people coming in to do dangerous things, and then work to protect the internal infrastructure - something that had never been done before - by analyzing and managing the risk, in partnership with the private sector."

Janet Napolitano, the governor of the Southwestern state of Arizona, has been named by President-elect Barack Obama to succeed Chertoff as Homeland Security Secretary.  Chertoff says he is sure that she will continue the legacy of success.

"I have perfect confidence in the dedication of my successor and the new administration," he said. "I believe they are as dedicated as we to protecting Americans.  And I believe they will want to carry on and discharge this most important obligation with as much vigor as we did."

Chertoff cautioned, however, that serious security threats remain.  He says that point was vividly underscored by last month's deadly attacks in Mumbai, India, which he says were skillfully coordinated and particularly targeted toward financial centers and Americans.