But the war also generated an enduring anti-war streak in Australian politics, a reaction to sending tens of thousands of men across the globe to die in a fight that, many felt, had no real bearing on Australia’s interests.

These divisions left a permanent mark, and anyone who wants to understand the country today needs to understand its role in the war, and the war’s role in its history. Consider, for example, the long-running debate over whether Australia should become a republic, a momentous decision for one of the largest members of the Commonwealth.

Both sides have used the war to justify their position. The pro-republic former prime minister Paul Keating has said that “out of the war came a lesson which transcended the horror and tragedy and the inexcusable folly” — namely, that everyday Australians must be their own sovereign, not a distant queen.

But others, like the present prime minister, Tony Abbott, argue that the war inextricably tied the country to the Commonwealth. Mr. Abbott even appointed a special minister to commemorate the centenary of Anzac Day (named for the Australia and New Zealand Army Corps, the unit that fought at Gallipoli), with a mission to present a celebratory account.

That same divide over the country’s relationship with Britain comes out in Australia’s foreign policy. The war’s apparent senselessness, and the way that it gave rise to the American superpower, drove a wedge between the country and Britain, and brought it more in line — militarily, but also economically and culturally — with the United States.

During World War II, the nation’s leaders were divided over whether loyalty to Britain and the war against Hitler should come before the alliance with the United States to defend Australia against Japan. Prime Minister John Curtin’s decision to bring Australian troops home from the Middle East settled the issue: His announcement that “Australia looks to America” has formed the basis of Australia’s defense policy ever since.

And yet those who recall the war as a glorious moment also have a point: Australia’s outsize role in contemporary global politics was bought with blood. It not only earned the country respect internationally, but it also focused a heretofore isolated and rural population toward the global stage, where it has sat ever since.