The currency crisis was engineerd to destroy the Yoruba and other Southern economy. A second by product is it enriches the Arewa and finally disturbs Tinubus and Obi ambition, acting as a conduit to keep power in Fulani hands.
For the mumu supporting the illegality, let me tell you a story. During the Brexit debates to take the UK out of the European Union the Boris Johnson government did not to take the matter to parliament even though it was a monumental decision. A lawyer took the UK to the Supreme Court and it ruled that the Executive ie the Government must enable a discussion on parliament. After this Brexit was discussed in Parliament. There's lots of other examples, but will just one today.
