Economic blockades are not new. The Peloponnesian War was triggered by one in the fifth century BCE; the Ottomans took Constantinople in 1453 after closing the Bosphorus. But targeted sanctions as a tool of peacetime foreign policy are a more recent innovation. In the aftermath of the First World War, liberal internationalists such as President Woodrow Wilson promoted them as a ‘peaceful, silent, deadly’ means of bending a rival’s will. Their first major test came with Italy’s invasion of Ethiopia in 1935. The failure of the League of Nations’ sanctions to prevent Mussolini’s occupation of Addis Ababa ruined the League’s reputation as an instrument of collective security. In 1941, Japan attempted to break free of a tightening US embargo by attacking Pearl Harbor. During the Cold War, embargoes became Washington’s favoured method of confronting communist countries while avoiding nuclear war; the embargoes implemented against North Korea in 1950 and Cuba in 1960 are still in force. From the 1970s, sanctions were used, frequently with the authorisation of the United Nations, to punish human rights violators and arms traffickers, to compel democratisation and to end apartheid in South Africa. They were generally more successful at impoverishing and weakening their targets than in forcing major changes to their behaviour or bringing about regime change. This was certainly true of the sanctions imposed on Iraq after the Gulf War of 1990-91, which did little to dislodge Saddam Hussein but caused a humanitarian crisis that sparked a global backlash (the first protests I joined were roadside anti-sanctions rallies in a New England town in the late 1990s). There was a growing sense in Washington that the success rate of sanctions did not justify their cost. In the case of Iraq, as it turned out, Plan B was invasion.
The disastrous wars in Iraq and Afghanistan made sanctions again seem a better alternative and their use rose dramatically. They have also grown more powerful, focusing on what Edward Fishman in his new study describes as one of the key ‘chokepoints’ in the world economy: control of the US dollar. Maritime trade has always had to negotiate geographic bottlenecks: the Suez Canal, for example, or the Malacca Strait or the Strait of Hormuz. Controlling these narrow passages, through which large volumes of trade pass, confers significant strategic advantages. Yet by the early 2000s, access to the dollar – used in around 90 per cent of foreign exchange transactions and accounting for roughly 70 per cent of foreign exchange reserves worldwide – seemed to offer even greater leverage.