Warning: if you work at PayPal, Square or even the credit card companies, you might not want to read this.

Arguably, the most important function the US Department of the Treasury undertakes is “to coin money” and create legal tender. This obligation was delineated in the Constitution itself — and it remains a core service of the US government to this day.

Which is why I do not understand how the US government can forsake this obligation so completely. Today, a vast portion of transactions are consummated with digital US dollars, yet the federal government does not provide for that legal tender. Instead, it outsources the “printing” of that money to PayPal, MasterCard, the banks, or pretty much any enterprise that wants to facilitate payments.

Now, the legacy argument that the federal government should not engage itself in this business of digital money relies on the notion that the government cannot do a good job at it. This is a weak argument. I was in Hong Kong last week, and I saw exactly how government can facilitate an effective digital payments program.

What you see above is the NFC checkout for the Octopus card, the prepaid card for using the Hong Kong transit system. The Octopus card started as the prepaid transportation card for the MTR, Hong Kong’s subway system. The card works great. In fact, it has worked so great that Hong Kong residents wanted to use the prepaid card elsewhere. So stores throughout the shopping capital of the world will include an Octopus card payment terminal. Octopus even included a rewards program. The card is used avidly by Hong Kong residents.

To be fair, MTR has morphed from a pure, government entity into a publicly traded corporation tied closely to its public service mandate. MTR’s privatization took place in 2000.

OK, so it is not an absolutely perfect model for the US, but it is an example of how government can facilitate digital currency, and it deserves Treasury’s consideration.