The US-China conflict gauge has moved from deep cooperation (post-Nixon, 1970s–1990s) to moderate tension (2015–2021), tracking trade frictions, technology competition, Taiwan tensions, and South China Sea disputes. Military strength rankings: USA still #1, China #2, Russia #3. The conflict gauge trending toward tension at a time when relative power is converging is the most dangerous configuration historically — rising powers in conflict with incumbents during power transitions have a poor historical track record of peaceful resolution.