More than 20 years after her resignation, the late British prime minister Margaret Thatcher remains a global brand. A memorable line from her 1980 Conservative Party conference speech, “The lady’s not for turning,” became her sales pitch. Like the marketing slogans printed on the labels of the tinned goods in her father’s grocery store, the words were her promise that no matter the circumstances, the product would always remain the same.

Yet in spite of her international profile, Thatcher never had a fully-fledged foreign policy. Her reputation in the UK rests on an economic program so experimental that it continues to spark controversy even today. Outside Britain, her economics mattered less, although she did become globally recognized as a staunch defender of capitalism and neo-liberalism. In the international arena, her name stands more for conviction politics—above all, the idea that that good politics begins with forthrightness and clarity.

It is easier to express Margaret Thatcher’s beliefs as a word cloud rather than a coherent political philosophy. She was for freedom, common sense, individualism, strength, independence, the rule of law and faith. She hated what she saw as their opposites: state control, intellectual waffle, collective action, compromise, negotiation, acts of terror and duplicity. The bottom line, however, was her love of clarity.

She was so ill at ease with ambiguity that even wordplay and puns made her uncomfortable, to the exasperation of her speechwriters. Her controversial economic theories were based upon an attempt to rekindle honesty in the marketplace. By squeezing out inflation, she hoped to make prices more “true,” and thus bring a new clarity to the business of buying and selling. She dreamed of a world where things do what they say on the tin, where products are dependable, prices are fair, and in business as well as politics, people know they are getting a square deal. Did she succeed?

Thatcher began her career as prime minister with a conference that saw the end of the white settler state of Rhodesia and the creation of Zimbabwe. She ended it by signing an agreement handing Hong Kong to China. In many ways, she represented the wing of her party most nostalgic for empire, yet she was realistic about saying goodbye to it. Nevertheless, she refused to allow the end of the British Empire to become the start of British decline. Like her four successors—John Major, Tony Blair, Gordon Brown and David Cameron—she judged that the best way to retain the trappings of a superpower was to keep close to the United States. Her great success was in carving out a relatively independent partnership.

Indeed, there were many moments when she led the way. She promoted the Polish shipyard workers’ union, Solidarity, which proved decisive in ending Communism and lobbied the US to retake Kuwait after the Iraqi invasion. But she was still constrained by American political interests. She never managed to halt the flow of American money to Irish Republican terrorists, for instance, due to the nature of Irish–American politics. Despite the fact that the IRA killed several of Thatcher’s closest colleagues and almost murdered her in the Brighton hotel bombing in 1984, Britain took second place to squalid politics.

Thatcher benefited from a strong personal sympathy with US president Ronald Reagan, who came to power twenty-one months after her 1979 election victory. Each seemed to regard the other as the senior partner. Reagan showed deference by asking Thatcher for advice, while Thatcher saw Reagan as an older, more charming and world-wise figure. Nevertheless, they had three major disagreements. When Argentina invaded the Falkland Islands and Thatcher responded by dispatching a naval task force, the US was a dubious ally, to say the least. The following year, the US illegally invaded Grenada with no attempt to inform the UK government, though Grenada is a Commonwealth country and its head of state is Britain’s Queen Elizabeth. Both events showed America in a poor light, willing to play fast-and-loose with international law in its “backyard” of Latin America and the Caribbean.

The third disagreement between Thatcher and Reagan clearly demonstrates the essential inequality between the US and UK. In 1986, America and the Soviet Union held a summit in Reykjavik, Iceland. Thatcher had met Reagan’s counterpart, Mikhail Gorbachev, before he became Soviet leader and she briefed Reagan that he was a man one could “do business with.” However, at Reykjavik, she was pushed out of the loop. The summit was convened to renew a ban on anti-ballistic missile systems. However, Gorbachev surprised the US by offering a formula to remove nuclear weapons from the European theater entirely. If the negotiations had been successful, it would have spelled the end of Britain’s missiles—thereby puncturing the myth that the UK operated an independent nuclear deterrent. In the end, the negotiations collapsed, yet the fact remains that when push came to shove, the US was willing to begin negotiations that cut into UK sovereignty.

Despite these disagreements, Thatcher maintained a partnership with the US that was as honest and equal as such a lopsided relationship could be. It helped that America regarded Thatcher as a totemic figure in the Cold War, a living embodiment of the Churchill-inspired mission to tear down the Iron Curtain across Europe.

However, her success as a Cold Warrior had a negative effect on wider foreign policy. Thatcher genuinely thought terrorism was obscene. She almost refused to meet Israeli prime minister Menachem Begin because of his involvement in the 1946 King David Hotel massacre. She was outraged when Israel conspired to murder Palestinian cartoonist Naji Al-Ali in London, and responded by expelling three Israeli diplomats and shutting the Mossad offices. Yet in the spirit of the age—or her perception of it—she regarded all terrorism as a manifestation of the Cold War, believing the Soviet Union and its satellites stood behind every terrorist operation. She was too easily persuaded by the disingenuous argument of the young Israeli ambassador to the UN, Benjamin Netanyahu, that terrorism could be defeated by military means without ever resorting to negotiations.

For many, the greatest black spot in her foreign policy is her hostility towards Nelson Mandela. She condemned him and his African National Congress party as terrorists, while vetoing attempts to impose sanctions on South Africa. Did she prolong apartheid? In truth, probably not. Indeed, by accepting the argument of apartheid-era South African prime minster P. W. Botha that the occupation of Namibia was necessary to protect South Africa from Cuban- and Angolan-led communist forces, she left Botha nowhere to go but the negotiating table once Reagan and Gorbachev backed a summit bringing peace to Namibia. After Namibian independence, apartheid fell almost immediately.

From the standpoint of 2013, Thatcher’s greatest foreign policy failure was not South Africa. Rather, it was her alliance with the Pakistani dictator General Zia Al-Huq. This was very far from being an open and forthright partnership. In fact, it was murky in the extreme. Zia was an ally in the clandestine war against the Soviet Union in Afghanistan, and the price of his loyalty was exorbitant. Pakistan’s development of nuclear weapons has led to nuclear proliferation from North Korea to Iran. The training camps in Pakistan’s northwestern frontier established by Afghan refugees became the cradle of Al-Qaeda-style terrorism throughout the world. In every respect, the relationship between Thatcher and Zia proves why the slogan “the enemy of my enemy is my friend” is the worst possible basis of foreign policy.

Margaret Thatcher battled for Britain by winning rebates from the European Union and acting as a freelance salesperson for UK plc, winning huge contracts for British business. Her greatest legacy, however, was her demand for outspoken clarity in international affairs. She rarely fell below her personal standards, yet on the few occasions she did, it proved fairly disastrous for the world.