The defining portrait of French freedom, La Liberté guidant le peuple, le 28 juillet 1830, by Eugène Delacroix has been defaced by a disturbed visitor to the new Louvre offshoot at Lens. The lower part of the canvas was blackened with a marker by a woman of 28, who was dragged off by guards before she could inflict too much damage. It was a major security breach and there will have to be an investigation. The consequence will be more barriers, more distance, between the public and the public art. Welcome to the 21st century.