Oil, the lifeblood of many countries that produce and sell it, appears to be rapidly turning into an ever-cheaper economic curse. A year ago, the international price per barrel of oil was about $103. By Monday, the price was about $42 , roughly 6 percent lower than on Friday. In oil -endowed Iraq , where an Islamic State insurgency and fractious sectarian politics are growing threats, a new source of instability erupted this month with violent protests over the government’s failure to provide reliable electricity and explain what has been done with all the promised petroleum money. In Russia , a leading oil producer, consumers are now paying far more for imports , largely because of their currency’s plummeting value. In Nigeria and Venezuela […]