“The Getty was the high bidder for the painting” – J.M.W. Turner’s Modern Rome – Campo Vaccino – “at an auction at Sotheby’s in London. But under British law, artworks of special significance that have been on British soil for more than 50 years can’t be sold and exported without a license – and the deal can be sunk if a British institution, or sometimes an individual, steps up to match what the foreign buyer was willing to pay.”