Imagine you possess the 15th-largest economy in the world. You have world-class cars and consumer goods, glittering streets and a lifestyle as good as any in the industrialized world.

Now, imagine you are being threatened by a hostile country one third as wealthy as Ethiopia.

Ethiopia.

In order to protect yourself from this economic juggernaut, you require the presence of nearly 30,000 American troops, the overpowering might of the U.S. nuclear arsenal and an American general to take charge in case this mighty opponent attacks.

Laughable, right? Not at all. Welcome to South Korea.

It’s time for the United States to leave the Korean peninsula. South Korea can defend itself.

Before the Korean War, the North was a relatively prosperous place, with the majority of the peninsula’s heavy industry and enormous mineral and timber wealth. South Korea was agrarian and poor.

In the six decades since the Korean War ended, the economies of North and South Korea have changed. Dramatically.

In 2012, South Korea’s GDP was $1.7 trillion. Per capita GDP for the South’s 50 million people was $32,400 in 2013.

North Korea, by contrast, has become spectacularly poor. GDP is a paltry $40 billion—$1,800 for each of 25 million people. North Korea is the world’s 182nd economy by GDP, poorer even than Ethiopia, Guatemala and Cuba.

By 2012, the South Korean economy was 41 times larger than North Korea’s.