The Church teaches as the viceroy of Christ the King what moral principles need to form economic laws and transactions.
Liberal Economic Philosophy says any choice which increases net wealth is a good choice; the principle acknowledges no limit.
If application of usury teaching was difficult in the sixteenth and eighteenth centuries, it is certainly more so today.
Usury is the sin of charging a profit or gain for the loan of something which is consumed in use such as money.
St. Thomas explains that the purpose of exchange transactions is to mutually benefit both parties.
Liberal Catholics who hold Capitalism to be an article of the faith love property, believing that it proves that the Church supports the Capitalist ethic.
Faced with an unprecedented economic crisis, many may be willing to consider ideas and principles which under more prosperous times were ignored.