In the dying days of his presidency, Barack Obama has reignited the debate over whether or not the U.S. should adopt a no first use policy – a pledge not to fire nuclear weapons unless first attacked by an adversary using them. According to reports, Obama is in favor of ruling out any first use of nuclear arms, much to the horror of security analysts and many of America’s closest allies. Officials and commentators from countries including Britain and South Korea have warned the Obama administration against making such a pledge, suggesting that doing so could seriously jeopardize not only U.S. security, but that of the entire Western world.

According to a report from the Washington Post, countries including Japan (which sits under the U.S. nuclear umbrella) believe a no first use policy might make conflict more likely, while permanent members of the U.N. Security Council such as France and the U.K. worry that such a pledge would create inconsistencies between their own nuclear policies and those of America, making coordination more complicated in the event of an emergency.