The US and Russia have agreed to remain committed to the nuclear deal that limits the number of nuclear warheads either side will hold in their stockpiles. Both sides have said that as long as the other remains committed, then no further nuclear weapons will be made or bought. But it seems difficult to trust anyone who has the power to wipe out entire cities with the press of a button, or even the ability to consider it. It is even more difficult to develop and maintain that trust when the targets include millions of children.