A week of talks between Iran and six powers over Tehran’s nuclear program made little headway in closing gaps on the most difficult issues, Western diplomats said Friday, though U.S. and Iranian envoys said a deal remained possible by the Nov. 24 deadline. Political pressures on the talks are likely to intensify rapidly if a deal isn’t done on time. U.S. lawmakers held off imposing additional sanctions on Iran when the first target date was missed in July, and the White House could struggle to hold new sanctions back after the midterm elections this fall. Iran has warned that could scuttle the diplomacy.