US President Barack Obama has conceded defeat in his efforts to close the U.S. military prison at Guantanamo Bay, Cuba. In a letter to Congress, sent on his last full day as President, Obama condemned lawmakers for placing politics above the ongoing cost to taxpayers. <br/><br/>Blaming the Congress, he said there is simply no justification beyond politics for the insistence on keeping the facility open. Obama pledged when he became President eight years ago to close the facility in his first year, but lawmakers in both political parties blocked that effort.