A military aide carries the so-called "nuclear football," which contains launch codes for the U.S. nuclear arsenal and which travels with the sitting U.S. president, to depart with U.S. President Donald Trump for travel to Utah from the White House in Washington, U.S. December 4, 2017.

The United States wants the rogue regime to give up its nuclear-weapons ambitions, and President Donald Trump aims to achieve that goal, possibly through direct diplomacy. The White House said Friday that Trump still intends to meet Kim by the end of May , following his on-the-spot acceptance of an invitation to talk.

The world's nuclear club is an exclusive group – and it has become even more dangerous with the relatively recent and unwelcome addition of North Korea and its leader, Kim Jong Un .

It might be too big a demand, however. North Korea is the only country to test nuclear weapons this century, and Kim has emphasized that nuclear weapons are a fundamental part of his regime's national security. And so the potential summit puts into motion the most significant development in years of intermittent negotiations about North Korea's nuclear weapons program.

North Korea is one of nine nations to have stockpiled nuclear weapons – about 14,500 total worldwide, a figure that has declined since the Cold War.

While the exact number of nukes in each country's arsenal is closely guarded, below is a breakdown of how many weapons exist, according to estimates from the Arms Control Association and Federation of American Scientists.

North Korea