The leaders of China and Iran agreed on a $400 billion economic and security deal last week, establishing a 25-year roadmap for deepened cooperation.

The agreement amounts to a diplomatic and economic lifeline for Iran, which has languished for years under the weight of US sanctions. For China, it announces the rising power’s arrival in a highly strategic region, and its growing willingness to engage directly in regional politics.

Does the China-Iran deal mark the beginning of the end of US hegemony in the Middle East, or is this another case of a moonshot investment accord whose projects never actually see the light of day?