If 1914 teaches anything, it is that great powers need at least a few clear reasons to step back from the brink. Finding those reasons will require more from Donald Trump and Xi Jinping than either man has so far been willing to give.

That is the core warning from Odd Arne Westad, a Yale professor of history and global affairs, in a new Foreign Affairs essay adapted from his forthcoming book, "Hvylya" reports. Whenever the two leaders meet for their long-promised summit in Beijing, the dangers of unbridled rivalry should be clear to both - yet Westad doubts either leader grasps what is required.

The problem is structural, not just personal. Trump is impulsive and "increasingly unsteady in terms of his overall aims," Westad wrote. Xi, while a superior strategist and the most powerful Chinese leader since Deng Xiaoping, sticks rigidly to his script. He "seems incapable of the private, spontaneous appeals to arrangements that could be part of a reordering of US-Chinese relations."

Both leaders have treated the relationship as a series of tactical exchanges - temporary truces on tariffs, stated intentions on narcotics control - rather than addressing the structural problems that drive confrontation. Westad argued this approach is dangerously insufficient. Without positive cooperation on underlying issues, the slide toward conflict will continue regardless of how many summits take place.

The stakes extend far beyond bilateral relations. An out-of-control conflict between the world's two leading economic powers could prove catastrophic for the entire international system. Westad pointed to 1914 as the cautionary tale: nobody saw the war coming, but afterward nearly everyone concluded it happened because great powers failed to solve the smaller conflicts that together fueled the disaster.

Earlier, "Hvylya" reported on why the Brookings Institution believes Trump's trade truce with Xi hangs by a thread.