In the iron triangle of politics, military, and economy, it's the economy that is the most important, and could be called the foundation of the triangle. After all, politics and military are essentially there to safeguard the economy.
Putting it more bluntly, whoever controls the world economy, controls the world.
At the heart of the economy are "supply" and "demand". By mastering these two origins and maintaining control over the circulation process, it's akin to holding the world's testicles. If you want someone to listen, just squeeze a little tighter. Should anyone dare to resist, simply crush their eggs.