Earlier quoted context omitted.
Congress deserves as much or more blame for this situation. They've prevented the President from carrying out his intended solution to this problem. Without their support, he is powerless to release these people.
dublinben: Can you substantiate your claim that Congress is responsible for this? Seems like Obama is the Commander in Chief and is the head of the Executive branch...
In a major rebuke to President Barack Obama, the Senate voted overwhelmingly on Wednesday to block the transfer of Guantanamo detainees to the United States and denied the administration the millions it sought to close the prison. The 90-6 Senate vote—paired with similar House action last week—was a clear sign to Obama that he faces a tough fight getting the Democratic-controlled Congress to agree with his plans to shut down the detention center and move the 240 detainees.
That's from 2009, but it's been an ongoing problem with defense funding bills since then.