The top U.S. and U.K. diplomats vowed to punish Russia with industrywide sanctions if this month’s Ukrainian presidential election is undermined as the Kiev government’s forces moved to flush out separatists in the east. “If Russia or its proxies disrupt the elections,” the U.S. and its allies “will impose sectoral economic sanctions as a result,” Secretary of State John Kerry said in London yesterday after meeting his counterparts from Britain, Italy , France and Germany . Pro-Russian separatists “are literally sowing mayhem,” seeking to “speak for everyone through the barrel of a gun.” Discord over the election risks another round of escalation as the Kiev government and its U.S. and European allies blame Russia for the unrest in Ukraine’s easternmost regions. Russian calls to include rebels in national unity talks that began May 14 were rejected as the meetings opened without separatist leaders’ participation. In eastern Ukraine, government troops […]