The Bulletin of the Atomic Scientists—founded by Manhattan Project scientists who invented the nuclear bomb, with 13 Nobel laureates on its executive board—has just moved its Doomsday Clock to 100 seconds before midnight. This marks the most severe security threat in its history.

The scientists are sounding the alarm not due to subjective fears caused by a mercurial and uninformed president with his finger on the nuclear trigger, but from a dispassionate assessment of terrifying realities. “Humanity continues to face two simultaneous existential dangers—nuclear war and climate change—that are compounded by…cyber-enabled information warfare, that undercuts society’s ability to respond,” reports the Bulletin. These dangers have become dire not simply because they are getting worse, but because “world leaders have allowed the international political infrastructure for managing them to erode.”

The threat posed by nuclear weapons has become more perilous because virtually the entire edifice of arms control (which at least added some stability to the nuclear face-off) is being dismantled. President Trump already deep-sixed the Intermediate-Range Nuclear Forces Treaty, and the last remaining arms-control treaty—the New START Treaty that capped Russian and US nuclear arsenals—is on the verge of expiring, with the Trump administration showing no sign of giving serious consideration to talks. The White House is considering withdrawing from the Open Skies Treaty that allows the United States and Russia to observe each other’s arsenals in monitored overflights. No substantive effort has been made to bring China into arms-control talks. Negotiations with North Korea have collapsed; its leader, Kim Jong-un, promises to unveil a new “strategic weapon.” Trump has pulled the United States out of the Iran nuclear deal, imposed severe sanctions and killed key military leader Qassim Soleimani. Tehran has responded by beginning to step away from the limits of the treaty and by increasing provocations in the region. The United States and Russia are on the verge of launching another nuclear buildup, with our country planning to squander another $1.2 trillion over the coming decades on the folly.

Read the full text of Katrina’s column here.