I'm not going to try and explain what Obama really meant. I'll leave that to others. Looking around the web found a couple of interesting articles.
First lets look at the legal definition of preventive Detention.
This from West's Law Encyclopedia:
http://www.answers.com/topic/preventive-detention
Preventive Detention
n.
The pretrial imprisonment without the right to bail of a person accused of a felony and judged dangerous to society;
The confinement in a secure facility of a person who has not been found guilty of a crime.
Preventive detention is a special form of imprisonment. Most of the persons held in preventive detention are criminal defendants, but state and federal laws also authorize the preventive detention of persons who have not been accused of crimes, such as certain mentally ill persons.
Preventive detention is a relatively recent phenomenon.
Preventive detention concerns imprisonment either without justification (the prisoner is not told the grounds for the arrest) or waiting for trial.
In most democracies, no one can be arrested without being told the grounds for such an arrest, except under rare and special circumstances (usually anti-terrorism legislation). An arrested citizen has to be brought before the nearest magistrate within a certain amount of time. The arrested person has the right to defend himself by a lawyer of his choice. Depending on the laws, this lawyer can be called for as soon as the detention starts, or sometimes days or weeks later.
However, there is an exception to this general provision. Under preventive detention, the government can imprison a person for some time. It means that if the government feels that a person being at liberty can be a threat to the law and order or the unity and integrity of the nation, it can detain or arrest that person to prevent him from doing this possible harm.
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There's more at the link. Supreme Court cases etc.
Now that we have the legalities covered what is the media saying about Oama's plan.
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Constitutional Law and Civil Right's Attorney Glenn Greenwald has an opinion:
http://www.salon.com/opinion/greenwald/2009/05/22/preventive_detention/index.html
Glenn Greenwald
Friday May 22, 2009 09:23 EDT
Facts and myths about Obama's preventive detention proposal
In the wake of Obama's speech yesterday, there are vast numbers of new converts who now support indefinite "preventive detention." It thus seems constructive to have as dispassionate and fact-based discussion as possible of the implications of "preventive detention" and Obama's related detention proposals (military commissions). I'll have a podcast discussion on this topic a little bit later today with the ACLU's Ben Wizner, which I'll add below, but until then, here are some facts and other points worth noting:
(1) What does "preventive detention" allow?
It's important to be clear about what "preventive detention" authorizes. It does not merely allow the U.S. Government to imprison people alleged to have committed Terrorist acts yet who are unable to be convicted in a civilian court proceeding. That class is merely a subset, perhaps a small subset, of who the Government can detain. Far more significant, "preventive detention" allows indefinite imprisonment not based on proven crimes or past violations of law, but of those deemed generally "dangerous" by the Government for various reasons (such as, as Obama put it yesterday, they "expressed their allegiance to Osama bin Laden" or "otherwise made it clear that they want to kill Americans"). That's what "preventive" means: imprisoning people because the Government claims they are likely to engage in violent acts in the future because they are alleged to be "combatants."
Once known, the details of the proposal could -- and likely will -- make this even more extreme by extending the "preventive detention" power beyond a handful of Guantanamo detainees to anyone, anywhere in the world, alleged to be a "combatant." After all, once you accept the rationale on which this proposal is based -- namely, that the U.S. Government must, in order to keep us safe, preventively detain "dangerous" people even when they can't prove they violated any laws -- there's no coherent reason whatsoever to limit that power to people already at Guantanamo, as opposed to indefinitely imprisoning with no trials all allegedly "dangerous" combatants, whether located in Pakistan, Thailand, Indonesia, Western countries and even the U.S.
(2) Are defenders of Obama's proposals being consistent?
During the Bush years, it was common for Democrats to try to convince conservatives to oppose Bush's executive power expansions by asking them: "Do you really want these powers to be exercised by Hillary Clinton or some liberal President?"
Following that logic, for any Democrat/progressive/liberal/Obama supporter who wants to defend Obama's proposal of "preventive detention," shouldn't you first ask yourself three simple questions:
(a) what would I have said if George Bush and Dick Cheney advocated a law vesting them with the power to preventively imprison people indefinitely and with no charges?;
(b) when Bush and Cheney did preventively imprison large numbers of people, was I in favor of that or did I oppose it, and when right-wing groups such as Heritage Foundation were alone in urging a preventive detention law in 2004, did I support them?; and
(c) even if I'm comfortable with Obama having this new power because I trust him not to abuse it, am I comfortable with future Presidents -- including Republicans -- having the power of indefinite "preventive detention"?
(3) Questions for defenders of Obama's proposal:
There are many claims being made by defenders of Obama's proposals which seem quite contradictory and/or without any apparent basis, and I've been searching for a defender of those proposals to address these questions:
Bush supporters have long claimed -- and many Obama supporters are now insisting as well -- that there are hard-core terrorists who cannot be convicted in our civilian courts. For anyone making that claim, what is the basis for believing that? In the Bush era, the Government has repeatedly been able to convict alleged Al Qaeda and Taliban members in civilian courts, including several (Ali al-Marri, Jose Padilla, John Walker Lindh) who were tortured and others (Zacharais Moussaoui, Padilla) where evidence against them was obtained by extreme coercion. What convinced you to believe that genuine terrorists can't be convicted in our justice system?
For those asserting that there are dangerous people who have not yet been given any trial and who Obama can't possibly release, how do you know they are "dangerous" if they haven't been tried? Is the Government's accusation enough for you to assume it's true?
Above all: for those justifying Obama's use of military commissions by arguing that some terrorists can't be convicted in civilian courts because the evidence against them is "tainted" because it was obtained by Bush's torture, Obama himself claimed just yesterday that his military commissions also won't allow such evidence ("We will no longer permit the use of evidence -- as evidence statements that have been obtained using cruel, inhuman, or degrading interrogation methods"). How does our civilian court's refusal to consider evidence obtained by torture demonstrate the need for Obama's military commissions if, as Obama himself claims, Obama's military commissions also won't consider evidence obtained by torture?
Finally, don't virtually all progressives and Democrats argue that torture produces unreliable evidence? If it's really true (as Obama defenders claim) that the evidence we have against these detainees was obtained by torture and is therefore inadmissible in real courts, do you really think such unreliable evidence -- evidence we obtained by torture -- should be the basis for concluding that someone is so "dangerous" that they belong in prison indefinitely with no trial? If you don't trust evidence obtained by torture, why do you trust it to justify holding someone forever, with no trial, as "dangerous"?
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There are 4 more questions concerning Preventive Detention at the link. He ended his article with 6 updates. I'll just post a couple:
UPDATE: Here's what White House Counsel Greg Craig told The New Yorker's Jane Mayer in February:
"It’s possible but hard to imagine Barack Obama as the first President of the United States to introduce a preventive-detention law," Craig said. "Our presumption is that there is no need to create a whole new system. Our system is very capable."
"The first President of the United States to introduce a preventive-detention law" is how Obama's own White House Counsel described him. Technically speaking, that is a form of change, but probably not the type that many Obama voters expected.
UPDATE IV: The New Yorker's Amy Davidson compares Obama's detention proposal to the internment of Japanese-Americans during World War II (as did Professor Amann, quoted above). Hilzoy, of The Washington Monthly, writes: "If we don't have enough evidence to charge someone with a crime, we don't have enough evidence to hold them. Period" and "the power to detain people without filing criminal charges against them is a dictatorial power." Salon's Joan Walsh quotes the Center for Constitutional Rights' Vincent Warren as saying: "They’re creating, essentially, an American Gulag." The Philadelphia Inquirer's Will Bunch says of Obama's proposal: "What he's proposing is against one of this country's core principles" and "this is why people need to keep the pressure on Obama -- even those inclined to view his presidency favorably."
UPDATE V: The Atlantic's Marc Ambinder -- who is as close to the Obama White House as any journalist around -- makes an important point about Obama that I really wish more of his supporters would appreciate:
[Obama] was blunt [in his meeting with civil libertiarians]; the [military commissions] are a fait accompli, so the civil libertarians can either help Congress and the White House figure out the best way to protect the rights of the accused within the framework of that decision, or they can remain on the outside, as agitators. That's not meant to be pejorative; whereas the White House does not give a scintilla of attention to its right-wing critics, it does read, and will read, everything Glenn Greenwald writes. Obama, according to an administration official, finds this outside pressure healthy and useful.
Ambinder doesn't mean me personally or exclusively; he means people who are criticizing Obama not in order to harm him politically, but in order to pressure him to do better. It's not just the right, but the duty, of citizens to pressure and criticize political leaders when they adopt policies that one finds objectionable or destructive. Criticism of this sort is a vital check on political leaders -- a key way to impose accountability -- and Obama himself has said as much many times before.
It has nothing to do with personalities or allegiances. It doesn't matter if one "likes" or "trusts" Obama or thinks he's a good or bad person. That's all irrelevant. The only thing that matters is whether one thinks that the actions he's undertaking are helpful or harmful. If they're harmful, one should criticize them. Where, as here, they're very harmful and dangerous, one should criticize them loudly. Obama himself, according to Ambinder, "finds this outside pressure healthy and useful." And it is. It's not only healthy and useful but absolutely vital.
OK there it is. It seemed clear to me back during the campaign that the only change Obama was offering was change from GOP lies and deceit to the same lies and deceit from the DEMS. This has got to wake up the mesmerized Obama suporters. If it doesn't then they cannot in no way, shape or form criticize Bush, Cheney, et al for what they did when they were in charge.
BTW doesn't this sound eerily like the movie Minority Report.