The life of the late Margaret Thatcher, former Prime Minister of the United Kingdom, offers many interesting and instructive examples of statesmanship. Not only for what the Iron Lady did, but what she did not do—her ability to resist the prevailing winds of peer pressure and public opinion in favor of her own principles. It is no surprise that this trait was exercised in matters great and small—for it was a virtue she refined over time.

One of the most humorous examples of Thatcher’s resolve was captured near the end of an obscure TV interview with a Swedish journalist, who asked Thatcher to jump up in the air as a way of humanizing herself to the audience. Thatcher firmly declined. “I make great leaps forward, not little jumps in studios,” she declared. “What a puerile thing to ask.” When pressed further and told that Gorbachev had jumped on command Thatcher asked, “I wonder what he thought about the politics of a free society if that’s what they ask you to do?”

This exchange reveals a gracious but unyielding loyalty to her principles and customs—a trait that allowed Thatcher to withstand the much stronger winds of national and international opinion when much more was at stake.

Criticized by many for being a woman in a man’s profession (by some for being too ladylike and by others for daring to enter politics at all), Thatcher maintained that a woman can contribute greatly even while refusing the masculine program of modern feminism. For example, she opposed women in military combat. “Women have plenty of roles in which they can serve with distinction: some of us even run countries. But generally we are better at wielding the handbag than the bayonet.”

When deeper European integration appeared to threaten British national sovereignty in 1990, Thatcher famously declared to the House of Commons, “No. No. No.” Her original impression proved correct about the anti-democratic and unaccountable structure of today’s European Union.

Likewise, having taken the reins with a stagnant British economy and general national decline, Britain’s first female prime minister said “no” to redistributive economic policies. When critics, media, and even voices in her own party criticized her curtailment of government spending she answered, “To those waiting with bated breath for that favorite media catchphrase, the U-turn, I have only one thing to say. You turn if you want to. The lady’s not for turning.” She refuted the arguments for socialism at every turn and made the case for true justice and equal opportunity in economic policy.

Along with President Ronald Reagan and Pope John Paul II, Thatcher mobilized moral and material resources against the menace of international communism. As John O’Sullivan described in his book about the historic trio, “Wojtyla, Thatcher, and Reagan all embodied such fading virtues as faith, self-reliance and patriotism—which the modern world seemed to be leaving behind.” Thatcher was quite comfortable standing athwart history and pointing to a happier, freer, and more sustainable future.

Collectivism was immoral and a national threat; the goal, therefore, was victory—not complacency. The strategic importance of resisting bad ideas and totalitarian leaders at every opportunity was a lesson of the Cold War that Thatcher feared might be lost on future generations. In her book—Statecraft—she wrote that if influential people fail to understand “or have just forgotten, what we were up against in the Cold War and how we overcame it, they are not going to be capable of securing, let alone enlarging, the gains that liberty has made.”

The capacity to say “no” at the right time to the wrong ideas is still an indispensable aspect of principled leadership. Young admirers of the Iron Lady must learn to exercise this virtue, too, for weightier decisions are coming. Today’s defenders of liberty need inner strength, refined by practice. In her words, “I have usually sought to avoid compromise, because it more often than not turns out to involve an abdication of principle.”

To be sure, statesmanship is not only about negation. There are many problems to solve, threats to face, and liberties to secure—and Margaret Thatcher was active on all fronts. But all these prospects are weakened or rendered unachievable without the ability to prioritize and the capacity to occasionally say “no.”