It much more closely resembles the British ill-conceived decision to enter World War I. It got into the war for ill-defined reasons, not really compelled by any treaty, it became embroiled in a bloodbath that cost Britain a generation of its youth, nearly bankrupted the nation, began the fracturing of the Empire, uprooted its entire social structure, invested the country in pacifism leading to Munich, and ruined the nation with cynicism.
As I recall, the British Foreign Minister of the time, John Kerry's equivalent as Secretary of State, had much to do with committing Great Britain to that terrible war.
