The president has asked Congress to consider establishing a special court or oversight board to authorise lethal action outside warzones under a new counter-terrorism doctrine which he says will end the "boundless war on terror".
But responses to his speech from leading campaign groups, though broadly welcoming, highlight how little change Obama is proposing to the underlying principle that the US has a legal right to kill suspected terrorists abroad without trial.
But he defended his administration's decision to launch hundreds of such strikes in recent years, insisting they were more discriminating than other military options such as aerial bombing and had helped prevent terrorist attacks....