Conventional wisdom among critics of Guantanamo is that preventive detention runs counter to the American civil rights tradition. Critics of the critics of course can point to previous wars in which enemy combatants were incarcerated until the war’s end. But now, a new study by Ben Wittes of Brookings Institution and Columbian Law student Adam Klein, published in the Harvard National Security Journal, provides the most thorough and objective account to date of the practice of preventive detention in the United States. And surprise, surprise … there is a rich history to the practice. As they note:

Preventive detention is not prohibited by U.S. law or especially frowned upon in tradition or practice. The circumstances in which it arises are not isolated exceptions to a strong rule against it; rather, they are relatively frequent. The federal government and all 50 states together possess a wide range of statutory preventive detention regimes that are frequently used, many of which provoke little social or legal controversy. The diverse statutes and regimes authorizing the preventive detention of individuals not convicted of a crime to prevent harms caused by that person range widely in purpose and subject matter: ·                     Wartime detention powers cover not merely prisoners of war and unlawful enemy combatants but also the nationals of countries against which the United States finds itself in a state of armed conflict; ·                     The Constitution’s Suspension Clause specifically contemplates that Congress might in crises suspend normal constitutional presumptions limiting detention–a power which has been invoked several times in American history; ·                     Detention authorities ancillary to the criminal justice system include both pretrial detention and the detention of material witnesses not even facing criminal charges; ·                     The immigration law permits the detention of aliens facing deportation and “arriving aliens” denied entry to the United States; ·                     State and federal laws permit the detention of the seriously mentally ill, when they pose a danger to themselves or to the public at large, as well as the detention of sex offenders even after they have completed their criminal sentences; ·                     State and federal statutes provide broad authority to quarantine people who have communicable diseases; and ·                     States and localities have a variety of protective custody powers, permitting the noncriminal detention–often for their own protection–of, among others, the intoxicated, alcoholics, drug addicts, the homeless, and pregnant drug users. The best way to understand preventive detention under American law and practice, we submit, is not that some broad principle prohibits it. It is, rather, that American law eschews it except where legislatures and courts deem it necessary to prevent grave public harms.

And as they also note, while the American legal tradition “tends to unapologetically countenance detention,” it does so “only to the extent necessary to prevent” public harm. And while many of these preventive detention practices have “narrowed over time,” the practice has expanded or contracted as local, state and federal governments and their publics perceive the need. The bottom line: If the practice of detaining terrorists and their supporters is judged to be “necessary and tailored to encompass only the truly dangerous,” Wittes and Klein argue, “it fits relatively comfortably in conceptual terms alongside the many powers state and federal legislatures have given governments to detain citizens and non-citizens alike.”