President-elect Donald Trump will take office on January 20. When that happens, he will be put in charge of the country’s stockpile of nuclear missiles, which means he could very well give the order to deploy one of those harbingers of death. But what would it take for President Trump — or any other leader of the United States — to actually use one of these missiles? What procedures have to be followed? What are the protocols?

The good news is that there isn’t a button in the Oval Office that a president can press to launch a nuclear strike. It’s a multi-step process involving top military officials from around the world (if nuclear submarines are involved) following a list of predetermined actions. The bad news is that most of these steps don’t mean anything; if Trump wants to nuke someone, Trump can nuke someone. Trump’s wildly varying opinions on nuclear weapons are well-documented, so it’s only natural to think about what he might do once he’s decided to use the ultimate weapon.

Step 1: The president meets with his advisers

The President of the United States (POTUS) has the ultimate authority to launch a nuclear missile. But he stills has to consult with his top advisers at the Pentagon and other branches of government before giving the order. This meeting doesn’t have to be long — the system is designed to be ready in case another country launches a nuke at the United States, which means it doesn’t allow a lot of time for dawdling — but it’s meant to ensure POTUS is of sound mind when they decide to order the launch of a deadly missile at somebody.

The football nuclear launch codes
From the Smithsonian National Museum of American History, the nuclear "Football."

Step 2: The order is given

Once the formalities are concluded, POTUS can decide whether or not to give the launch order. This can be done in one of two ways: Either from a secure station, of which there are several across the United States, or from a briefcase called “the Football” that contains everything needed to authorize a nuclear strike. This includes a secure communications tool, a book with the launch codes, and information about where the nuclear arsenal.

Step 3: The order is sent down the chain of command

Using the Football or one of the secure stations, the order is passed down from POTUS to the Pentagon’s war room. The senior officer in the war room reads a so-called challenge code to verify that the order is actually coming from POTUS; a laminated card called “the biscuit” is then given to POTUS. The biscuit has information about the challenge codes and their matching responses. If POTUS gives the correct response, the order passes down the chain of command.

USA nuclear sites
A map of major nuclear sites in the contiguous U.S. Grayed-out sites are not currently active.

Step 4: The launch order goes out

The war room then prepares a launch order with information about the target, the time to launch, and the codes needed to unlock the nuclear missiles before they are fired. This launch order goes out to submarine and intercontinental ballistic missile (ICBM) crews who use them to prepare to launch the missiles.

Step 5: The crews take over

Submarine and ICBM crews follow slightly different procedures from here. On a submarine, a captain, executive officer, and two other crew members verify the order. The order gives them the combination to a safe with a “fire-control” key that allows them to deploy the missiles. About 15 minutes later, the missiles are ready to launch.

ICBM crews, on the other hand, are distributed throughout the country. Five crews of two people each receive the launch order, open safes containing SAS codes, and make sure everything lines up. The missiles are then retargeted based on the war plan, and the five crews simultaneously turn their keys to let the missiles know it’s time to launch. Only two crews have to authorize the launch, however.

Step 6: The missiles are launched

Assuming POTUS has given an order, the Pentagon has passed it down the chain of command, and the crews tasked with launching the missiles haven’t mutinied, the nuclear launch then begins.

That’s how it works. Let’s hope it never has to actually go down.

Photos via Jamie Chung, Wikipedia, Getty Images / Joe Raedle