Five years ago, the United States was struck by the most devastating terrorist attack in its history. Subsequent investigations indicated that al-Qaida - a radical Islamic group led by Osama bin Laden - was responsible for the terrorist assaults that killed almost 3,000 people. As a response, the Bush administration instituted some domestic changes.
The September 11, 2001, terrorist attacks on the United States prompted the Bush administration to launch its global "war on terror." Five years later, that struggle continues, and experts believe it will for a very long time.
The 9/11 attacks brought changes to the American national scene. Airport security has been tightened. Tougher immigration procedures have been put in place. More than 20 agencies have combined to form the new Department of Homeland Security, and intelligence services have been restructured.
In addition, new laws have increased domestic law enforcement powers. In a speech September 7 in Atlanta, President Bush defended his decision to allow the National Security Agency - or N.S.A. - to conduct electronic surveillance operations in the United States without warrants.
"At my direction, the National Security Agency created the Terrorist Surveillance Program," he said. " Before 9/11, our intelligence professionals found it difficult to monitor international communications, such as those between al-Qaida operatives secretly in the United States and planners of the 9/11 attacks. The Terrorist Surveillance Program helps protect Americans by allowing us to track terrorist communications, so we can learn about threats like the 9/11 plot, before it is too late."
A federal judge last month declared the N.S.A.'s actions illegal and unconstitutional - a ruling the Bush administration is appealing.
Civil libertarians have criticized the N.S.A. program and other measures - such as parts of the counterterrorism "Patriot Act" - as being too intrusive. But the Bush administration says those measures are needed to fight terrorism.
Danielle Pletka from the American Enterprise Institute, says she would like to see stricter measures.
"I would like to see a far more intelligent means of scrutiny at airports. I would like to see the visa system for students change significantly, and no longer be in the hands of universities to make decisions about whether to issue visas or not, as it currently is," she said. "I would like to see fundraising for terrorists made extraordinarily more difficult. It is really, really easy to raise money for a terrorist organization and send it overseas."
Experts say it is a very delicate balance to protect a nation from terrorism, while at the same time safeguarding essential democratic freedoms. Former Defense Secretary William Cohen.
"We have to be very wary of how we maintain a free and open democratic society, and, at the same time, call upon the government to protect us, and to save us from this kind of violence that is being directed towards us," he said. "Should we have the government in possession of data that is all encompassing and all inclusive about each and every one of us? Is that something that leads us more and more to a sort of 1984 Orwellian nightmare, where we have the government watching each and every one of us - where is the limit? So, those are the kinds of issues that civil libertarians are correct in raising, and we ought to have a healthy debate about it, but be very conscious of the fact that the more we see attacks coming at us, the greater the demand will be for more security and less liberty."
Brian Jenkins is a leading expert on terrorism, working for the RAND Corporation. He says many western nations, such as Italy, Germany and Britain, have increased domestic surveillance programs to fight terrorism, while remaining democratic countries. Jenkins says they did so by working within the laws and rules governing democracies.
"It is when we operate outside of the rules, when there are assertions of unlimited authority, as a result of the president's war-making powers under the Constitution," he noted; "it is when we begin to collect intelligence outside of the judicial processes that have been established to govern that; it is when we begin to detain people outside of some reasonable judicial process, or at least fair process; it is when we begin to treat prisoners outside of the rules that have been established, not only internationally, but within our own code of dealing with those in our custody, that we run into trouble."
Jenkins says as long as there is an open and healthy debate within any democratic society about what measures are needed to protect against terrorism, that democracy will continue to flourish.