Three generational forces will converge this week — first in Washington, then in Beijing — in what could prove a hugely consequential stretch of Donald Trump's presidency. Why it matters: The coming days carry stakes measured in decades: war and peace in the Middle East, the trajectory of the U.S.-China relationship, and the rules governing the AI revolution . State of play: Trump's China summit was once seen as a de facto deadline for stabilizing the Iran war. But with Air Force One set to land in Beijing on Wednesday evening, the conflict remains unresolved. On Sunday, the U.S. finally received Iran's response to a one-page memorandum aimed at ending the war and establishing a framework for nuclear negotiations. Trump rejected the offer as "unacceptable" and accused Iran of "playing games" with the U.S. — leaving him days to recalibrate, escalate or arrive in Beijing empty-handed.…