Given that we were being sued for 20 million there was plenty of reason for the Government to settle.  The Government has already lost 3 court cases brought by Omar Khadr - the last which resulted in him being repatriated from Cuba.  Given that the 4th suit was for damaged arising from the previous 3 cases he won there was little chance of the Government winning the case when we have already spend 5 million fighting him.  Main civil suits settle to contain costs and that is what happened.