The cover-up has to stop – and with it, the huge sums in aid for a country with oppressive policies towards Palestinians

• Desmond Tutu is a Nobel peace laureate and a former archbishop of Cape Town

Every recent US administration has performed a perverse ritual as it has come into office. All have agreed to undermine US law by signing secret letters stipulating they will not acknowledge something everyone knows: that Israel has a nuclear weapons arsenal.

Part of the reason for this is to stop people focusing on Israel’s capacity to turn dozens of cities to dust. This failure to face up to the threat posed by Israel’s horrific arsenal gives its prime minister, Benjamin Netanyahu, a sense of power and impunity, allowing Israel to dictate terms to others.