By Paul Reynolds
World affairs correspondent, BBC News website
Sir Ken Macdonald, the outgoing Director of Public Prosecutions for England and Wales, said in his final speech on 20 October: "We need to take very great care not to fall into a way of life in which freedom's back is broken by the relentless pressure of a security state."
Guantanamo Bay has been at the centre of the debate on civil liberties
But as governments react to the changing threats posed since the 2001 terror attacks on the US, what has been the impact on civil liberties in western societies?
Guantanamo Bay, military tribunals, renditions, water-boarding, warrantless surveillance - all these have been part of US policy since 9/11.
In the UK, meanwhile, detention without charge for 28 days (and an attempt to extend that to 42 days), control orders and more data collection are now facts of life.
These measures demonstrate that the system of protecting civil liberties has creaked and sometimes cracked in two of the countries most at threat from terrorist attacks.
"For the first couple of years after 9/11, the Bush administration fought terrorism without regard for human rights," said Kenneth Roth, executive director of Human Rights Watch in New York.
But in the last two years, Mr Roth said, there had been "a reaffirmation of human rights and a scaling back of the worst abuses".
Mr Roth said upholding human rights was a better way of improving security
"[US President George W] Bush said the secret CIA sites would be closed temporarily and it seems they have not been used since.
"Congress has laid down that inhumane treatment should not be used anywhere in the world and the US army produced a good field manual on interrogation which should now be extended to the CIA as well.
"The CIA lives in its own world, however. This remains a big issue for the next US president.
"So does Guantanamo, which should be closed and the detainees either tried in the US or released."
Aiming for balance
For many governments, the key issue has been how to balance civil liberties against civil security.
British Home Secretary Jacqui Smith said earlier this year: "The Prevention of Terrorism Act 2005 strikes the right balance between safeguarding society and safeguarding the rights of the individual."
Britain has been successful in prosecuting cases through the normal courts. There has been no recourse, as there was in Northern Ireland, to abolish jury trials. But there has been controversy.
Jacqui Smith says current anti-terror legislation strikes the right balance
The balance in the UK recently swung back when, after strong opposition, the government dropped its proposal to extend no-charge detention for up to 42 days.
Under the Human Rights Act that incorporates the European Human Rights Convention into British law, UK courts have also held up the deportation of suspects to countries where torture might be used against them. This is currently under appeal.
Britain still hopes to develop a huge database of e-mail and telephone traffic, collecting addresses and numbers that could be used to track terrorist contacts - something opponents fear will be used on so-called fishing expeditions by intelligence services.
It is also still using control orders (currently imposed on 16 people) though again the courts have set limits, for example to the hours someone can be confined indoors.
The Bush approach
President Bush, on the other hand, tends to use the word "balance" in a different way.
In his State of the Union address in January he said: "This war is more than a clash of arms - it is a decisive ideological struggle, and the security of our nation is in the balance."
In such a war, he feels, strong methods are required. He can argue that he has stopped any further major attacks since 9/11.
George W Bush has made tightening up US borders a priority
American tactics often impact externally because that is where the main threats to the US have come from, as on 9/11 itself. There is the additional constraint from the US constitution internally, which requires the normal use of the criminal law.
Therefore, tightening up US borders has been a priority. The latest device is to require of EU countries that they send no less than 19 sets of details about air passengers, including details of any special diets requested and credit cards used.
The threat to the UK has more often come from internal sources, usually from young Muslim men radicalised by religion and world events.
Britain also has a large population with a family background in Pakistani Kashmir, where a tradition of militancy against India can easily be swung into antagonism against the West.
Therefore, British anti-terrorism strategy has concentrated more on internal threats.
As well as the intelligence and police campaigns against actual perpetrators, this strategy has added political, educational and persuasive tactics to prevent people from turning to terrorism in the first place.
A new round of discussions about the direction of this strategy is to begin in January.
In a major speech about new trends in terrorism on 15 October, Ms Smith said: "This new terrorism actively seeks to recruit people in this country and to subvert our institutions.
"It has a detailed public narrative that claims to justify the killing of civilians. But it has more than this - it also has the electronic means to disseminate that narrative very quickly and very widely."
While critical of the lengthy no-charge detention period in the UK, Kenneth Roth of Human Rights Watch also criticised France, which he said has too low a threshold for evidence, including hearsay.
This can lead to a lengthy detention under the holding charge of "criminal association".
In his opinion, the country which seems to come out best is Spain.
"Despite the [Basque separatist group] ETA threat and the Madrid bombings, Spain has in many ways proved to be a model among governments because it has prosecuted in the usual way," said Mr Roth.
This, he said, supported his argument that security and human rights are not at opposite ends of the spectrum: Maintenance of human rights is a better way of improving security.
"Abuses are a boon to terrorist recruiters," said Mr Roth. "There has been a recognition that the breaking of terrorist conspiracies depends less on interrogation than on the cooperation of the public.
"If the public sees itself as complicit in a dirty war, especially if a community identifies itself with the suspects, that makes it harder."
Breaking the rules
How is this all seen by the Human Rights Commissioner for the Council of Europe (COE), the body that oversees the European Convention on Human Rights, the bedrock of human rights in its 47 member states?
The commissioner is Thomas Hammarberg, a Swede who once headed Amnesty International.
"I think that governments have tried to stretch and break the rules," he said. "The proposed British 42-day legislation was not in the spirit of the Human Rights convention."
He added that the military commissions at Guantanamo Bay broke trial procedures.
"The defendant should be able to see all evidence," said Mr Hammarberg. "There should be well-founded grounds for any detention.
"As for the 'balance' concept, I avoid the word. Human rights and civil liberties should apply in all situations. Rights are most relevant when there is a threat or a crisis.
"I am extremely worried about the data protection aspect the moment. The danger is that there will be more trawls through the data bases according to pre-determined profiles. This is already happening.
He said he was also concerned by the EU agreeing to supply the US with details about air travellers.
Not everyone sees data bases and other intelligence-gathering operations in a dark light.
Dr Philip Davies, a security expert and lecturer at the UK's Brunel University in London said a data base for e-mail and phone calls was not a "vacuum cleaner".
"It is a microscope," he said. "You have to understand that to get at a few bits of information you have to gather lots if it. The civil liberties argument is certainly overstated.
"It is not unreasonable to try to keep track of certain communications. Critics often talk about the fantastically improbable as if going after one intercept is going after them all."
Data collection is shaping up to be another battleground. Paul.Reynolds-INTERNET@bbc.co.uk