If one episode sums up Margaret Thatcher’s instinctive, no-nonsense approach to international affairs, it was her appearance in Aspen, Colorado, in August 1990. Staying at the country home of the US ambassador to London, Henry Catto, Thatcher was informed that Saddam Hussein had invaded Kuwait.According to her memoirs, Thatcher went for a short walk to sort out her ideas and then, within hours, was laying down the law in person to a slightly bemused President George Bush (the elder).

First, she said, Britain and the US were not in the business of appeasing dictators—an obvious reference to her successful stand against Argentina’s junta in the Falklands crisis, as well as Winston Churchill’s defiance of Hitler.

Second, she warned that if Hussein were not stopped, Saudi Arabia and most of the west’s oil reserves in the Gulf could soon be under his control.

Bush agreed, but was initially reluctant to contemplate sending troops to the Middle East to expel Iraq from Kuwait. Growing exasperated, Thatcher told the president during a subsequent phone conversation that “this is no time to go wobbly”.

There were other mutterings about backbone and the like.

Bush got the message eventually, announcing that he was “drawing a line in the sand”. Despite entreaties from Egypt’s president, Hosni Mubarak, and others to allow an Arab solution, Bush told Hussein to get out or face military action. In the event, he was evicted in 1991 in Operation Desert Storm—the first Gulf war.Thatcher’s international standing, or at least her profile, was already high, long before the Gulf crisis. Her period in office saw a series of momentous global challenges, culminating in the impending implosion of the Soviet Union and the end of the cold war. In much of this, Britain was often intimately involved.

Despite the rhetoric of subsequent prime ministers, it was perhaps the last time that fading British power really did punch above its weight.

The underlying principle, or article of faith, in all that Thatcher did abroad was informed by a close, preferably inseparable, alliance with the US—a maxim adopted by her successors, notably Tony Blair.

In Ronald Reagan, who became president in 1981, she found a political soulmate and fellow arch-conservative with whom she eventually became a close friend as well as an international ally.

With Thatcher, however, chumminess did not translate into slavishness. When Reagan ordered the invasion of Grenada, a Commonwealth member, in 1983 without first informing her, Thatcher was furious and told the White House so.

But on the most pressing issue of the day—the climax to the cold war with the Soviet Union and the Warsaw pact - Thatcher and Reagan saw eye to eye. It was Thatcher who bought the Trident nuclear missile system, upping Britain’s nuclear deterrent to new levels. It was Thatcher who allowed the US to secretly deploy Pershing and cruise missiles on British soil—a deployment exposed by the Guardian. It was Thatcher who stubbornly ignored the subsequent protests at Royal Air Force Greenham Common.

Unlike her US counterpart, the British leader was quick to see changes afoot behind the iron curtain. While Reagan toured West Berlin, urging the Soviet president, Mikhail Gorbachev, to “tear down this wall”, Thatcher saw in Gorbachev a new type of communist, open to ideas of reform. He was, she said, “a man with whom I can do business”.

The Russians nicknamed Thatcher the Iron Lady out of a mixture of awe and fascination. It was a label that stuck. And it was one that the leaders of Britain’s allies - notably Francois Mitterrand, then president of France, and Helmut Kohl, the West German chancellor - had good cause to ponder.

Thatcher’s battle to win a European Economic Community budget rebate for Britain - she referred to it as “my money” - won her the political enmity of much of Europe. Mitterrand said she had the “look of Caligula and the mouth of Marilyn Monroe”. It was a measure of his impotence in the face of the Thatcher onslaught that he was reduced to sexist stereotyping.

Kohl’s grievance was more justified. Fearing that a more powerful Germany might once again pose a threat to Europe (and British influence), Thatcher opposed German reunification after the Berlin Wall came down in 1989 and the eastern European satellites broke away from Moscow.

In this, with or without hindsight, the British leader was clearly on the wrong side of history, as was also the case when she refused to back sanctions against apartheid South Africa. On Europe, as elsewhere, Thatcher relied too much on the past to inform her view of the future. Would her hero, Churchill, have made the same mistakes? Churchill was an ardent pro-European and no friend of the Boer, so one suspects not.

In her noted speech in Bruges in 1988, Thatcher positioned herself firmly against the nascent European Union and its federalist instincts. Her assertion that Europe was about free trade, not supranational authority, has been followed by British Eurosceptics ever since. It is, perhaps, her most lasting and most divisive international legacy.

By arrangement with the Guardian