To stop carmakers bending the rules on emissions, Europe must get much tougher

AMERICA’S system of corporate justice has many flaws. The size of the fines it slaps on firms is arbitrary. Its habitual use of deferred-prosecution agreements (a practice that is spreading to Britain; this week Rolls-Royce, an engineering firm, was fined for bribery—see ) means that too many cases are settled rather than thrashed out in court. But even crude justice can be better than none. To see why, look at Europe’s flaccid approach to the emissions scandal that engulfed Volkswagen (VW) in 2015 and now threatens others.Diesel-engined vehicles belch out poisonous nitrogen-oxide (NOx) gases. Limits have been imposed around the world on these toxic fumes. But the extra cost of making engines compliant, and the adverse impact that this has on performance and fuel efficiency, tempt carmakers to flout the rules. That is easier to get away with in Europe than in America, where the regulations are tighter and enforcement is more rigorous.