To misquote John Maynard Keynes: if you’re owed a few million, it’s your debtor’s problem, but if you’re owed billions it’s your problem. And China is owed a cool $50bn by Venezuela in loans made in prepayment for crude deliveries according to Reuters: the FT puts the total owed at $65bn.

Venezuela has never consistently delivered the full contractual volumes envisaged under the 2008 loans-for-oil deal. With the country’s output and exports falling, and...