Can US, North Korea 'trigger' nuclear strike?

Is there really a red button on the desks of leaders which they can press to trigger off a nuclear strike?

In the United States, the so-called red button is a real metal briefcase.The military aid accompanying the president always carries this metal briefcase. 

The briefcase and its cover weighing about 20 kg are also known as the Atomic Football, the Black Box or even the "Button".

It consists of four items which include two books, a folder and a small card. 

One of the books is black in colour and lists the options open to the launching country for retaliation. 

The other book lists out site locations of where the President can be whisked away to safety.

A small folder contains a description of procedures for the emergency alert system, while the card includes the authentication codes on it. 

To launch a strike the President will first decide on which weapons are to be launched. Next, his order will be verified by the secretary of the defence. Then, the president has to identify himself to the joint chiefs of staff through his personal code. It is only after all these steps that nuclear weapon would be launched. 

Procedures vary slightly in different countries but there you have it. It is not as easy as President Trump and North Korean leader Kim Jong Un seem to make it believable. 

 In short, the red button does not exist.