The US and UK have fought two major wars and disagreed on modern interventions:
WWI, WWII, Korea, Gulf War – close allies.
Iraq War (2003): UK joined US-led invasion without UN mandate. Massive controversy, damaged trust, sparked protests in both nations. WMD claims proved false.
Strong alliance: intelligence (Five Eyes), trade, defense, nuclear cooperation. Disagreements persist (e.g., Iran deal, ICC, climate pace) but institutional ties are deep.