The latest spasm of violence in the Middle East has sent crude-oil prices climbing in recent weeks, a familiar action-reaction that frequently has proved to be a drag on economic growth. Yet that dynamic figures to ease in coming months and years as U.S. dependence on Mideast oil is, by a variety of measures, at a generational nadir. In the current flare-up of unrest, Islamist militants have swept across northern Iraq, threatening Baghdad and spurring fears that violence could disrupt the country’s 2.7 million barrels a day in exports. Amid this, the U.S. crude-oil benchmark on the New York Mercantile Exchange has climbed to around $107 a barrel, the highest level since September. The oil-price instability has been playing out broadly since late 2010, when a string of popular political revolutions across the Middle East drove up the price of crude to $113 a barrel from $85 over five […]