North Korea's latest Hwasong-18 intercontinental ballistic missile – its first ICBM to use solid rocket fuel – has reignited debate over possible Russian links to the nuclear-armed state's dramatic missile development. In a report published on Thursday by the Washington-based Center for Strategic and International Studies, Theodore Postol, professor emeritus at the Massachusetts Institute of Technology, argued that the Hwasong-18 ICBM is likely the result of technical cooperation sourced to Russia. The Hwasong-18 has been tested twice, including on July 12 in what was the longest flight time ever for a North Korean missile test. It is the North's first…