"The Iron Lady" is the name of the new film in which Meryl Streep stars as Margaret Thatcher. You have only to consider the title itself to understand the impact of the person portrayed. It helps explain why, in these hard times, she and her legacy arouse even more interest than they did in the boom era at the end of the 20th century.

First, the word "Lady." Mrs. Thatcher was the first and only woman ever to have led a major British political party, and remains so to this day. She was the first woman prime minister in the English-speaking world and the longest-serving British prime minister of either sex since universal suffrage.

Even in 2011, only one important Western country—Germany—is led by a woman. Whatever the sterling qualities of Chancellor Angela Merkel, one must judge it highly unlikely that she will be the subject of a major feature film 20 years after she retires. Mrs. Thatcher was, in effect, the one and only woman. That unique status still fascinates.

And this Lady was first called "Iron" not by her admirers but by her enemies. After becoming leader of the Conservative Party in 1975, Mrs. Thatcher opened a new, controversial front in the Cold War with the Soviet Union. She questioned the then fashionable idea of "detente." Soviet communism, she argued, should not be accommodated. It should be overcome—by repairing the defensive military strength of the NATO alliance and by holding out to the subjugated peoples of the Soviet bloc the promise of Western liberty.

Not many people in the West agreed with her at the time, except one Ronald Reagan, and he was just an ex-governor of California with a dream of running for president.