President Trump started 2018 with a tweet chiding North Korea's leader Kim Jong Un that “he

too has a nuclear button”....

And it's “bigger and more powerful” than Kim's

But launching a missile involves much more than pushing a button.

And really, there is no button.

Here's what would actually need to happen.

The president must first discuss the plan with a group of military and civilian advisers.

That group includes the Pentagon's deputy director of operations, and the head of U.S.

Strategic Command- anyone else in the group is at the President's discretion.

The call either takes place in the White House Situation Room or the president can be patched

in on a secure line.

Some of the advisers may try to change the president's mind or resign in protest, but

ultimately, the Pentagon must do whatever the commander-in-chief orders.

That meeting with advisors can be as short as 30 seconds.

Next the president gives the order to launch.

But before the Pentagon can prepare the launch order, it must first verify that the

person ordering the strike is indeed the president.

An officer in the Pentagon's war room reads what's known as a “challenge code”.

For example, “Delta-Echo.”

The president retrieves the “biscuit,” a laminated card the president or a military

aide carries at all times, and finds the matching response to the challenge code:

For example, “Charlie-Zulu”.

Once the codes match, the launch order goes out.

The war room prepares a message containing the war plan, time of launch, authentication

codes and the codes needed to unlock the missiles before firing them.

That message is only about 150 characters long

It's encoded, encrypted and broadcast to launch crews.at this point only about 2-to-3

minutes may have passed since the initial conference call.

Within seconds, a submarine and five ICBM crews in various underground bunkers receive

the launch orders.

They open safes and compare their Sealed Authentication System codes (SAS) to those sent by the war

room.

This will confirm that the order is authentic.

If the codes match, the crews enter the war plan number into their launch computers.

They type additional code to unlock the missiles, and at the designated time of launch, the

five crews simultaneously turn a launch key retrieved from their safe…

It only takes two crews to launch, so three can refuse to do any of the prior steps and

the missile or missiles will still fire.

For missiles are launched from a submarine, there is no second key - the crew has full

power to launch.

From here, there is no turning back.

It's been about AS LITTLE AS 5 minutes from the time the president decided to launch a

nuclear missle to the time the missle or missile(s) blast out of their silos.

It will take submarine missiles an additional 15 minutes until they shoot out of their tubes.

Once it fires, a missile and its warhead cannot be called back.