Permabanned
This is Rachel Maddow she states in this clip...Obama is stating that he'll keep people in detention because they MIGHT commit crimes in the future.
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.
Source - http://en.wikipedia.org/wiki/Preventive_detention
President Obama’s proposal for a new legal system in which terrorism suspects could be held in “prolonged detention” inside the United States without trial would be a departure from the way this country sees itself, as a place where people in the grip of the government either face criminal charges or walk free.
Mr. Obama has so far provided few details of his proposed system beyond saying it would be subject to oversight by Congress and the courts. Whether it would be constitutional, several of the legal experts said in interviews, would most likely depend on the fairness of any such review procedures.
Ultimately, they suggested, the question of constitutionality would involve a national look in the mirror: Is this what America does?
“In our constitutional system,” Mr. Obama said, “prolonged detention should not be the decision of any one man.”
But Mr. Obama’s critics say his proposal is Bush redux.
Mr. Obama’s proposal, Professor Hakimi said, appears to be “an aggressive approach that is not commonly taken in other Western developed countries.”
In a letter to the president on Friday, Senator Russ Feingold, Democrat of Wisconsin, said he was not sure Mr. Obama’s idea would prove constitutional, and added that “such detention is a hallmark of abusive systems that we have historically criticized around the world.”
Source - http://www.nytimes.com/2009/05/23/us/politics/23detain.html?_r=1&hp
So now it starts, he pretends things will change, yet as you can clearly see here, things aren't.