The challenges facing the society of states today are a direct consequence of the strategic innovations that won the Long War—the development of nuclear weapons, a global system of communications, and the technology of rapid computation.

These have undermined the ability of any nation state to govern its economy; to assert its laws in the face of universal norms of human rights; to defend its territory against weapons of mass destruction; to tackle transnational problems like global warming, epidemics and terrorism; and to protect the national culture from outside influences.

The Shield of Achilles puts the subject of the State back on the table for constitutional theorists and historians after a long period in which other subjects—rights, for example—had eclipsed its centrality.

Book I, State of War, describes a two-way, mutually affecting causal process that mediates between fundamental changes in the constitutional basis of society and deep innovations in its military strategy.

This methodical if unorthodox sequencing allows the historian to avoid the tempting mechanics of foreshadowing, emphasizing the possibilities of different outcomes at each stage, and deepening the understanding of how the past can liberate the present.

These wars were all fought over a single set of constitutional issues, to determine which form of constitution – liberal democracy, fascism or communism – would replace the colonial ideology of the imperial states of Europe that had emerged after the epochal Napoleonic Wars that had dominated the world between the Congress of Vienna and August 1914.

Bobbitt traces this perspective of military history via Thomas Hobbes and Niccolò Machiavelli to Thucydides.

Eric Hobsbawm introduced a similar idea in The Age of Extremes (1994), where the period from 1914 to 1991 is called the short twentieth century.

Public officials who followed Bobbitt's works included Prime Minister of the United Kingdom, Tony Blair;[2] the Archbishop of Canterbury, Rowan Williams, who built his Dimbleby Lecture around Bobbitt's thesis [3][4][5] and the former United States Secretary of State Henry Kissinger[6] The Shield of Achilles was the 2003 Grand Prize Winner of the Hamilton Awards and the Arthur Ross Book Award Bronze Medalist of the Council on Foreign Relations for Best Book in Foreign Policy of that year.

British military historian Michael Howard wrote, The Shield of Achilles "will be one of the most important works on international relations published during the last fifty years", and Paul Kennedy, writing in The New York Review of Books argued that it may "become a classic for future generations."

In contrast, Paul W. Schroeder, acknowledging that his view was "evidently a minority one," judged that the book is "error strewn," "suffers from grand delusions of theoretical adequacy," and "is unscholarly.