Go into almost any shop and hear Christmas carols and read signs trumpeting enormous discounts. Unusual, since the scramble for discounts traditionally begins after, not before, the first turkey has made the ultimate sacrifice to celebrants of Thanksgiving. By the end of next week, 45 million turkeys will have moved from farm to plate to palate, and the discount wars will be in full flow. Best Buy, the recovering appliance chain, has vowed to match the prices of discounter Walmart’s, which in turn pledges to undersell Best Buy and everyone else who dares to compete with it during what it is predicting will be a shopping season battered by political paralysis, government spending cuts and a weak recovery. Lest those pledges of competitive mutual assured destruction result in a downward price spiral to zero, the various sellers will offer slightly different, difficult-to-compare models, a ploy that will not prevent margins from becoming razor-thin.

Still, slight profits are better than none at all. Most merchants can live with thin margins if they have to, so long as merchandise is flying off the shelves. That is especially important this year: retailers’ inventories shot up recently, and will leave stores with unwanted stocks of unsold goods as they enter the new year unless trade is brisk.