The US detention facility at Guantánamo Bay has become a stain on the United States' reputation. Shutting it down will cause new problems. Rather than hold terrorism suspects in preventive detention, the United States should turn them over to its criminal justice system.

The best solution would be to prosecute them, either in civilian courts or before regular courts-martial. US courts have a long history of successful terrorism prosecutions, including most recently Jose Padilla, but the administration claims the courts are not up to the task.

Its preferred alternative – special military commissions – suffer serious due process problems, such as permitting the use of coerced testimony. Even in the unlikely event that military commissions survive judicial challenge, they would be a public-relations calamity, drawing far more outrage to their unfair procedures than to the alleged crimes of the suspects on trial.

Another alternative, currently being floated in academic and legal circles and likely soon to surface in Congress, would be a system of preventive detention. It would permit the long-term detention of terrorist suspects in the United States after some kind of a hearing but without criminal charges or trial. All that would be required would be some claimed proof of dangerousness.

By regularizing such a massive loophole to our basic due process rights – an exception that invites abuse – the "solution" would be worse than the Guantánamo problem. But there is no need to contemplate such a radical departure from American tradition, because the assumption that the regular courts cannot handle terrorism cases is wrong.

The most common argument against such prosecutions is that they examine crimes that were already committed, while the danger of terrorism is said to be so great that it requires preventing acts before they occur. But the crime of conspiracy can be both backward and forward looking. Under US law, a conspiracy can occur whether or not an intended illegal act is completed. All that is needed is that two or more people agree to pursue an illegal plan and that one takes any step to advance it. Similarly, the crime of providing "material support" to a terrorist enterprise does not require a completed act of terrorism.

These crimes provide ample latitude to address the terrorist threat. The same intelligence that allows investigators to identify a terrorist plot should allow them to prosecute the participants before they actually commit an act of terrorism.

Another objection is that under the US Constitution, a suspect facing criminal charges is entitled to a lawyer, who typically will tell his client not to talk. Interrogators naturally prefer the greater flexibility to question people facing preventive detention.

But even many criminal suspects with lawyers end up talking, because doing so can shorten the prison time they face. Moreover, if a suspect's right to counsel is violated, the Constitution prevents use of the fruits of an interrogation only by the people involved in prosecuting that suspect. Other investigators playing an urgent preventive role are free to question a suspect so long as they do not pass anything said, or leads from it, to the suspect's prosecution team.

Some contend that prosecution is impossible because US officials have subjected so many terrorism suspects to torture and other harsh interrogation, the fruits of which no ordinary judge would admit at trial. But such coercive interrogation is illegal. We should not compound the harm by using that illegality to justify preventive detention.

Moreover, a review of hearings held so far at Guantánamo shows that the government has plenty of evidence unrelated to abusive interrogation – computers and cellphones seized, conversations intercepted, even witnesses who have cooperated voluntarily. We should not assume that coerced confessions are the only route to criminal conviction.

But what if some suspects cannot be prosecuted – because there is no evidence that they participated in criminal activity or because the government contends that established court procedures for protecting sensitive intelligence are insufficient? In that case, it may be necessary to release a suspect. The person would still be placed under surveillance, but he would not be detained.

That involves some risk, but a policy of preventive detention carries its own risks. One lesson of Guantánamo is that if the United States begins detaining people on the basis of thin or untested evidence, it inevitably ends up detaining innocent people. Particularly when combined with "harsh" interrogation, that generates resentment and a sense of victimization in their communities. The resulting animosity is a boon to terrorist recruiters and undermines the popular cooperation that is far more important than interrogation for uncovering secret terrorist plots.

Before discarding America's criminal justice system, we should keep in mind the old adage: if it ain't broke, don't fix it. That is especially true when the alternative of preventive detention would breach our most basic due process rights.

This piece was originally published in Foreign Affairs

Kenneth Roth, a former federal prosecutor, is executive director of Human Rights Watch