How Giants Fall: The Unmaking of Four Empires

By the 4th century Rome was no longer the empire of the early principate. The reforms of Diocletian and Constantine had made it larger but more rigid: a swollen army, crushing taxes, a debased currency. In 375, the westward push of the Huns drove the Goths to the Danube — some 200,000 refugees begging to be let in. The eastern emperor Valens allowed the crossing, then let border officials plunder them until the Goths rose in revolt.

On 9 August 378, at Adrianople, Valens attacked without waiting for reinforcements from the West. The legions were annihilated and the emperor killed on the field. Rome could never push the barbarians back out again; it could only settle them inside as "allies." In 410 the Visigoth Alaric sacked Rome itself — the first time in eight centuries. In 476 the Germanic general Odoacer deposed the last emperor, Romulus Augustulus, and did not even bother to claim the throne — he simply submitted to Constantinople. The Western empire vanished without a sound.

What a vast system already overdrawn in finance and military strength fears most is not a mighty rival, but a single badly-handled shock at the border.

The 19th-century Ottoman Empire was called "the sick man of Europe." Spanning three continents and ruling dozens of peoples for six hundred years, it had fallen behind in the race to industrialize. The 1908 Young Turk revolution tried to save it through constitutionalism, but a 1913 coup handed power to the "Three Pashas" military clique, led by the fervently pro-German Enver Pasha (age 32).

When war broke out in 1914, the Ottomans could have stayed neutral. But Enver secretly allied with Germany and plunged in that November — a gamble that ended in disaster: Gallipoli held, but the Arab, Caucasus, and Mesopotamian fronts all collapsed; the wartime genocide of the Armenians became a permanent stain. Defeated in 1918, the empire was carved up by the Allies. In 1919 a Greek landing at Smyrna instead ignited the national resistance led by Mustafa Kemal. In November 1922 Kemal abolished the sultanate; the 1923 Treaty of Lausanne fixed the borders of the Turkish Republic, and six centuries of empire formally ended.

An already-weakened multi-ethnic system, plus one strategic misjudgment about "which side to join," is enough to turn chronic decline into sudden death.

Victory in WWII had hollowed Britain out. It won the war but ran up huge debts and lost solvency, surviving on American loans. In 1947 it was forced to give up India, "the jewel in the imperial crown"; yet London still saw itself as a first-rate world power. Prime Minister Anthony Eden was determined to preserve that illusion.

In July 1956 Egypt's President Nasser nationalized the Suez Canal — Britain's lifeline to the East. Eden cast Nasser as "a new Hitler" and secretly plotted with France and Israel to seize it back by force. They struck in late October and won quickly on the ground. But U.S. President Eisenhower was furious: he would not push the Arab world toward the Soviets in the Cold War, and resented being bypassed by his allies. Washington refused to prop up the plunging pound and threatened to dump it; Britain's reserves emptied within days. Eden had to withdraw in humiliation, mid-victory.

When a great power's global commitments outrun its economy, what it can actually do is often decided by its creditors, not its armies.

In 1991 the USSR still looked like a superpower: nuclear weapons, an army, eleven time zones. But it was in essence the last multi-ethnic continental empire. Gorbachev's perestroika (restructuring) and glasnost (openness) were meant to save it, but they loosened fear — its one and only binding hoop. From 1990, the three Baltic states were the first to demand independence.

On 19 August 1991, hardliners launched a coup while Gorbachev was on holiday, sending tanks into Moscow. But Russian Federation President Boris Yeltsin climbed onto a tank in open defiance, and the coup collapsed in three days. The irony: what broke it was not liberals' loyalty to the USSR, but the Russian nationalism in Yeltsin's hand — he wanted Russia, not the Soviet Union. On 8 December, the leaders of Russia, Ukraine, and Belarus met secretly in the Belovezha forest and declared by a single accord that "the USSR as a subject of international law ceases to exist." On 25 December Gorbachev resigned and the red flag came down.

A vast structure held together by fear, once the grip loosens even slightly, collapses faster than anyone expects — including the one who loosened it.