It’s also possible that insiders belonging to the Libra cartel could exploit their access to information, business relationships or technology to give themselves advantages. There are many ways a new currency system could advantage large businesses over everyone else, especially when the large ones are sitting on the board of governors for the payments system. For instance, one of the incentives being discussed to get people to use the currency is discounts on Uber rides; if this happens, Facebook would be giving an advantage to Uber instead of other ride-sharing businesses.

The third problem is that the Libra system — or really any private currency system — introduces systemic risk into our economy. The Libra currency is backed, presumably, by bonds and financial assets held in reserve at the Libra Reserve. But what happens if there is a theft or penetration of the system? What happens if all users want to sell their Libra currency at once, causing the Libra Reserve to hold a fire sale of assets? If the Libra system becomes intertwined in our global economy in the way Facebook hopes, we would need to consider a public bailout of a privately managed system.

Sorry, but no thanks: We should not be setting up a private international payments network that would need to be backed by taxpayers because it’s too big to fail.

And the fourth problem is that of national security and sovereignty. Enabling an open flow of money across all borders is a political choice best made by governments. And openness isn’t always good. For instance, most nations, especially the United States, use economic sanctions to bar individuals, countries or companies from using our financial system in ways that harm our interests. Sanctions enforcement flows through the banking system — if you can’t bank in dollars, you can’t use dollars. With the success of a private parallel currency, government sanctions could lose their bite. Should Facebook and a supermajority of venture capitalists and tech executives really be deciding whether North Korean sanctions can succeed? Of course not.

A permissionless currency system based on a consensus of large private actors across open protocols sounds nice, but it’s not democracy. Today, American bank regulators and central bankers are hired and fired by publicly elected leaders . Libra payments regulators would be hired and fired by a self-selected council of corporations. There are ways to characterize such a system, but democratic is not one of them.

Years ago, Mark Zuckerberg made it clear that he doesn’t think Facebook is a business. “In a lot of ways, Facebook is more like a government than a traditional company,” said Mr. Zuckerberg. “We’re really setting policies.” He has acted consistently as a would-be sovereign power. For example, he is attempting to set up a Supreme Court-style independent tribunal to handle content moderation. And now he is setting up a global currency.