The growing tensions between the United States and Russia may lead to a nuclear war and destroy humankind, an American writer and retired professor says. As tensions between Moscow and Washington spike over the Syria conflict, “we could head into a nuclear conflict which would devastate humanity,” said James Petras, who has several books on Middle Eastern political issues. “We need to move away from this saber-rattling from Washington into a position that could come to terms with peaceful co-existence, but I don’t see that on the horizon in present or the near future with either Hillary Clinton or Donald Trump as presidential candidates,” Petras told Press TV on Tuesday.