Visa and MC are, as mentioned, an effective duopoly over card payments in the EU. This means that Visa and MC are in a position to govern the flow of money.

Visa and MC are, as mentioned, an effective duopoly over card payments in the EU. This means that Visa and MC are in a position to govern the flow of money. Since they have started acting as a governing body by unilaterally cutting off access for political reasons, they have exposed themselves to political control over their behavior, also for political reasons. Only the government gets to be the government. That's why it works.