Tom Ridge

The Department of Homeland Security, whose creation amounted to the largest government reorganization in half a century, remains a work in progress, as its leader, Tom Ridge, acknowledges.

"The attacks of 9-11 required a whole new philosophy of how we secure the country," said Tom Ridge. "And, as we shore up one vulnerability, we more than likely work to uncover another."

And he's not the only one saying the agency needs to do more. Former Virginia Governor Jim Gilmore headed a commission that assessed the nation's ability to respond to a terrorist attack.

"There's still more that needs to be done," he said. "Specifically, I think we have to be concerned about the possibility of a bioterrorism attack."

Robert Mueller

And this from terrorism expert Neil Livingstone.

"We're safer than we were a year ago, safer than we were on 9-11," said Neil Livingstone. "But we're not as safe as we could be. We've got a long way to go."

Homeland Secretary Ridge agrees but thinks private industry and ordinary Americans also have to do more.

"Our goal over the next year will be to accelerate the basic level of citizen preparedness across this country, whether that's by preparing the family ready kits and emergency plans, volunteering to aid in disaster planning, engaging in training exercises to help someone in a life threatening situation," he said.

Intelligence sources say electronic eavesdropping on suspected terrorists leads them to believe al-Qaida and its sympathizers remain committed to attacking the United States again. FBI Director Robert Mueller.

"There are strong indications that al-Qaida will revisit missed targets until they succeed such as they did with the World Trade Center," said Robert Mueller. "And the list of missed targets now includes both the White House as well as the Capitol."

Ed Markey

Because of that, the nation's capital has undergone many changes, with government buildings and monuments surrounded by police checkpoints and barricades. Once open avenues are now blocked and anti-aircraft missiles are deployed at key sites near the White House and the Pentagon.

Around the country, security gaps remain, including at the nation's borders. Democrats in Congress have released a report accusing the Bush administration of failing to address what they say are glaring shortcomings in protecting the homeland, especially the nation's air and seaports. Congressman Ed Markey.

"A young man was able to nail himself into a box and ship himself across the country," said Ed Markey. "Another young man was able to sneak boxcutters onto a passenger plane."

Uninspected cargo arriving at the nation's seaports poses another potential hazard. Democrat Linda Sanchez represents a portion of Long Beach, California, home to one of the world's busiest ports.

Linda Sanchez

" Seven million cargo containers enter this country via seaports every year and yet we all know by now that just a small amount are checked," said Linda Sanchez. "These largely uninspected and unsecured containers crisscross the country's cities by truck and by rail."

But terrorism expert Neil Livingstone says the biggest weakness in homeland security so far is the inability to keep track of people entering the country, something he and other critics say the Department of Homeland Security and its $30 billion annual budget fail to adequately address.

"The greatest vulnerability we have today probably is a single suicide bomber stepping into a crowded shopping mall or an athletic event," he said. "To prevent that, we need better border security than we have today and that means also immigration security in terms of our visa program, who we let in this country and what type of effort we make to monitor people who come into this country."