On January 20, 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.

Taking nuclear weapons off high alert would not impede our country's ability to defend itself. We could still respond to an attack. But it would buy time for the president to consult with Congress and other leaders and for cooler heads to prevail. We should not rush into a decision to start nuclear war.

As Obama said in 2008: "Keeping nuclear weapons ready to launch on a moment's notice is a dangerous relic of the Cold War. Such policies increase the risk of catastrophic accidents or miscalculation. I believe that we must address this dangerous situation."

Now, President Trump could launch 140 warheads in the time it takes to write 140 characters. The grave difference is: a tweet can be deleted, but the devastation of a nuclear warhead can never be undone.

Sign this petition to call on President Obama to use his authority to take nuclear missiles off hair-trigger alert status.

Then, share this petition with your friends, family, and co-workers. Together, we can make sure these weapons are never used again. www.ploughshares.org