President Obama on Thursday pledged to use his last 18 months in office to work on gun control, calling it “the one area where I feel that I’ve been most frustrated and most stymied.” “If you ask me where has been the one area where I feel that I’ve been most frustrated and most stymied, it is the fact that the United States of America is the one advanced nation on earth in which we do not have sufficient, common-sense gun safety laws – even in the face of repeated mass killings,” he told the BBC in an interview. “And...