Within days following the attack, Congress pushed through the USA PATRIOT Act, providing unprecedented authority to the US federal government.

The legislation also gave several government agencies sweeping powers over the US banking system. And they made an important discovery.

You see, the entire world relies on the US banking system… at least for now.

The US dollar is still the world's most dominant reserve currency.

Oil contracts around the globe from Iraq to Indonesia are settled in US dollars.

Foreign governments and central banks hold US dollars as their reserves.

And the US dollar is widely used in global trade. When a Vietnamese manufacturer sells to a Ukrainian wholesaler, that deal will transact in US dollars.

This widespread use of the dollar means that the US banking system is essential to global commerce.

International banks must have access to the US banking systems so that they can transact in US dollars.

Being shut out of the US banking system would be disastrous for a foreign bank because they'd no longer be able to do business in US dollars with the rest of the world.

This gives the US government enormous leverage over global banks. And they realized this in 2001.