Effective accountability is the key point in Ms Jolene Tan Siyu's letter ("Respond to terror threats with due process"; Forum Online, May 10).
A vigorous pursuit of terrorist-related activities might result in mistakes. Therefore, Ms Tan is concerned with the appropriate boundaries of state power.
She believes the justificatory process of a person involved in potential terrorist activities lies in a court of law and not preventive detention.
Her position makes a few suppositions about potential terrorist activities as crimes, and a court's role in these cases.
I have three points to make in response.
First, terrorism is some form of violence perpetrated by non-state actors against state authorities. In this sense, the perpetrators can be regarded as criminals and their actions can be treated as a criminal act.
But it is not always possible to put terrorist criminals through the ordinary criminal process.
These detainees can belong to a powerful group, such as the Islamic State in Iraq and Syria, or have the capacity to intimidate or harm those who give evidence against them in a court of law.
Second, the courts continue to maintain a broadly restrained approach, especially in jurisdictions which permit some form of review over a detention's legality.
In the cases of Hamdan v Rumsfeld (2006) and Munaf v Geren (2008), the United States Supreme Court reviewed the legal process against abusive cases of detention. But it did not rule that detention was illegal per se.
In 2005, Britain's highest court ruled that evidence which was procured by torture was inadmissible, only because there was no legislative authorisation. In other words, the evidence would be admissible had the British Parliament expressly authorised it in legislation.
Third, the judicial restraint reflects the recognition of a government's institutional competence in terrorist-related activities, which often involve foreign policy.
Ms Tan said that arguments of legality should be presented by "trained counsel". This is possibly an overstatement.
In the US case of Hamdi v Rumsfeld (2004), it was suggested that arguments could be made in military tribunals, and that hearsay evidence could be admitted, without offence to due process.
In Britain, special advocates, as designated by law, argue cases in closed sessions: Once they are privy to closed materials, they cannot take full instructions from the detainee whom they represent or call witnesses.
Daniel Seah Chin Aun