President Trump raised concerns when he argued on Twitter that he has a “bigger and more powerful” nuclear button than North Korean leader Kim Jong Un.

In reality, there’s no button. Instead, it’s a protocol designed to allow the President to quickly launch a nuclear strike.

The president still has the sole authority to launch a nuclear attack, though the Senate Foreign Relations Committee held a hearing in November to assess possible changes to that process, and there is an ongoing debate about ways to reform the process.

“I assume the president knows there is no button and he was speaking euphemistically and to let it be known that he has the sole ability to order the use of a far larger number of nuclear weapons than Kim Jong Un,”said Kingston Reif, the Director for Disarmament and Threat Reduction Policy at the Arms Control Association.

Here’s how the president would actually launch a nuclear weapon.

Trump decides to order an attack or a counter-attack

Should a nuclear attack on the United States be imminent, Trump would receive information from the nuclear command and control system about it, and the President would typically confer with his military advisers before making a decision on how to respond.

It’s also possible that the president could decide to preemptively launch a nuclear strike.

As a congressional primer on the procedure notes, the United States has no rules against a preemptive strike, but some in Congress have argued that, in that case, the president should not have the sole power to to do this and should require additional approval.

Either way, however, the next step is for Trump to identify himself to the command center who can actually implement the strike.

Trump identifies himself to the Pentagon

As President, Trump carries an ID card known as the “biscuit” that enables him to identify himself to officials at the Pentagon with unique codes letting them know he is authorizing a nuclear strike. He would also need to specify the type of attack he wanted to carry out; the different options are delineated in the nuclear football.

The U.S. has 800 warheads that are available for use within minutes of ordering a nuclear launch, says Reif; Approximately 400 warheads that are land based intercontinental ballistic missiles and roughly the same amount of submarine launched ballistic missiles.

(As a side note, a former Chairman of the Joint Chiefs of Staff claimed in a 2010 memoir that an aide to President Clinton lost the biscuit and hid the mistake for months.)

Strategic Command launches the missiles

Once Trump has successfully conveyed his orders, Strategic Command, which has operational control over U.S. nuclear forces, would implement them. Reif says that the process of launching the warheads should take a little over 15 minutes—less if you don’t use submarine launched ballistic missiles—a system that was designed during the Cold War, when it was believed that the Russians had warheads that could reach the United States in under 30 minutes. If only

“Deterring such a threat and responding to such an attack was thought to require the capabilities to rapidly launch us weapons before Soviet warheads could detonate on U.S. soil and that would have left very little time for the president to consult with his advisers. Hence the consolidating authority in the hands of the President alone,” Reif explained.

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Write to Alana Abramson at Alana.Abramson@time.com.