North Korea has continued to test ICBMs but has not yet managed to attach a nuclear warhead to one. Photo / AP
Every day for two years, Peter Hefley would drive through Wyoming farmland to work, hoping he wouldn't be called upon to act.
The nuclear launch officer, then 25, was one of two people who worked in an Air Force command and control centre deep underground from 2005 to 2007, maintaining a squadron of 50 of the world's most devastating missiles and waiting for instructions to launch.
"If you imagine a hardened bunker 60 feet below the ground, that's what we were doing," he told news.com.au.
"Each [missile] had up to three nuclear warheads on it. Any one of those warheads would just destroy a city regardless of size."
But while he used to have confidence in the fact Commander-in-Chief at the time, George W. Bush, would follow an escalation process from diplomacy to a declaration of war and use of conventional weapons first, now he has no such confidence.
"It's fear," he said when asked what led him to speak out given his critical former role. "It's being afraid that not only can I picture myself, now there are kids doing what I did and the atmosphere is completely different.
"I'm nervous as a citizen because this is scary. Something that can devastate a good portion of the globe is on the hairpin trigger."
The former college space hacker who ended up on the Air Force's missile programme said he now wants people to realise just how quickly a disaster could occur.
"The most important thing everybody can understand is how quick that process can happen because everybody is trained to do it as fast as possible," he said about the system that can take just four minutes from the President's order until the first missiles leave their silos.
The stark warning comes as a leaked draft of the Trump Administration's Nuclear Posture Review (NPR) showed plans to increase "low yield weapons" that will not rely on host nations for support and are designed to ensure a "prompt response".
Separately, US Air Force psychiatrist Steven Buser told the New York Times "warning signs abound" when thinking about whether Trump would pass the military's strict Personnel Reliability Program (PRP) for fitness to serve in that role.
While the White House has said the NPR does not represent official policy, the report describes "low yield weapons" — the same force as those dropped on Hiroshima and Nagasaki — as a "low cost and near term modification that will help counter any mistaken perception of an exploitable 'gap' in US regional deterrence capabilities".
Critics, including Hefley, argue it could lead to a terrifying proliferation of the weapons the world is supposed to be eradicating, in the context of an unstable political environment.
"This is the first time I've heard in my lifetime [an argument for] restocking the nuclear armament. Everything has been a take down because they realise the devastation. This is 'let's add to this and let them do more things that will let us use more nuclear weapons'."
The comments come after Trump's escalating rhetoric with North Korean leader Kim Jong-un and brags that his "nuclear button" is bigger and readily available. Trump supporters claim his hardline approach has helped force North Korean concessions including diplomatic talks with South Korea.
Hefley is one of 17 former nuclear launch officers who has recently signed an open letter stating Trump is "worse than we feared" when it comes to his temperament to be Commander-in-Chief.
Global Zero executive director Derek Johnson, who wants to see nuclear weapons abolished, said the Nuclear Posture Review's new stance takes the country closer to the "point of no return".
"Trump's plan to develop so-called 'low-yield' nuclear weapons and loosen restrictions on their use is a dramatic departure from longstanding US policy that makes nuclear war more likely. The world is about to get a whole lot more dangerous," he said.
"Once we cross the nuclear threshold, all bets are off. If a nuclear weapon is used, nobody on the receiving end is going to stop to measure the mushroom cloud before retaliating. This plan paves a road to disaster."