Barack Obama has been urged to take the US nuclear weapon arsenal off a state of high alert before president-elect Donald Trump takes the reigns to stop him "impulsively blowing up the planet".
The Ploughshares Fund, nuclear experts who have advocated for nuclear disarmament since the Cold War, have started a petition calling on Obama to take the weapons off "hair-trigger status" before he leaves office on 20 January.
They say a man of Trump's temperament should have to seek Congress' approval before launching the weapons so "cooler heads can prevail".
The petition states: "On 20 January, the military officer carrying the codes for America's nuclear arsenal will follow President Barack Obama to the inaugural platform. When he leaves, the officer will follow President Donald Trump.
"We will then have a president who reportedly said, 'If we have nuclear weapons, why can't we use them?'
"Will he really order a nuclear attack in the next four years? No one knows. But if he does, no one can stop him.
"President Trump will be able to launch, within minutes, one or one thousand nuclear warheads without any vote, any check, or even any serious deliberation. Just one missile could kill millions. Once launched, the missiles could not be recalled.
"But President Obama has one last chance to reduce this danger. With the stroke of a pen, he can take US nuclear missiles off hair-trigger alert, so that any attempt to use these weapons would take hours or days."
Last month, Joseph Cirincione, President of the Ploughshares Fund, wrote an opinion article for the Huffington Post, in which he said: "It's too late to stop Donald Trump from becoming president. But it is not too late to stop him from impulsively blowing up the planet."
The petition has been signed by over 65,000 since it was launched.
Tom Collina, Ploughshares Fund's director of policy, told the Independent the petition had been started amid concerns about Trump's impulsive nature.
"Our proposals would build in some extra time, and to make take longer to launch," he said. "The concern is mainly about false alarms. That is when you need cool heads. If you have someone who is impulsive…"
There have been numerous reported incidents over the past 30 years of the US believing it was under attack from the Russians, only to discover – with just minutes before a potential launch – the threat was in truth a computer glitch or else a Scandinavian weather satellite.
"President Trump could launch 140 warheads in the time it takes to write 140 characters," the petition added. "The grave difference is: a tweet can be deleted, but the devastation of a nuclear warhead can never be undone."
However, the US president cannot order a nuclear weapon to be launched alone, due to a "two-man rule". Another senior member of the National Command Authority – which the current secretary of defense, the vice-president and their deputies – must confirm the president's launch order is valid, before it passed down the chain of command.