It is not enough to be; one must do!

That adage aptly sums up the theme of The Iron Lady, the new biopic starring Oscar-nominated Meryl Streep as Margaret Thatcher. While some in Britain are questioning the scenes of Mrs. Thatcher in a state of old-age dementia, as a leadership drama it is masterful. Through flashbacks of key moments of Thatcher's leadership life, the film explores the nature of power and its impact on self and others.

Viewers learn that Margaret's desire to make a difference was shaped by her strong relationship with her father, a grocer, and mayor of Grantham in the East Midlands. Her spine was stiffened by her determination to succeed in the rough and tumble—and dominantly male—world of British politics. It was this drive that propelled her to speak her mind, make her mark, and eventually to become Britain's first—and only—woman Prime Minister.

Such is the drive that serves her in good stead as she fights the twin demons of this drama, the Irish Republican Army, and the militant trades unions. Peace in Northern Ireland would elude her administration. But Thatcher did break the stranglehold of union militancy and championed free enterprise that ushered in a new era of prosperity.

Another theme that runs through the film dwells on the personal cost that Mrs. Thatcher bore simply because of her gender. Her quest for relevancy meant that she had to make sacrifices at home that at times strained relations with her husband and twins. Every woman in a position of power can certainly bear witness to the struggle that Thatcher endured simply to be considered seriously.

The moral of this film—and one that resonates with leaders today—is that the quest for power does have limits. In short the same pushing to be heard that gets you considered for a position of authority must be tempered when finally reaching that position of power. Mrs. Thatcher, after becoming one of the longest-serving Prime Ministers in history, was ousted by members of own party. Many were simply tired of her single-minded and heavy-handed management style. 

One scene should make every leader cringe. It features Thatcher at a Cabinet meeting snatching a document from one of her most trusted aides. As she copyedits it, she makes disparaging comments about the document and its author. No doubt many viewers will have witnessed scenes such as this when a top boss berates a subordinate over trivial matters. Mrs. Thatcher's petulant cruelty demonstrates that she and she alone is in charge. Lord Acton's mantra that power corrupts and absolute power corrupts absolutely is on full display.

Leaders who succeed are those who believe in their ability to make a positive difference. Yet sometimes, as shown in the story of The Iron Lady, too much belief in oneself leads to arrogance, hubris, and eventually undoing.

(This article first appeared on Feb. 2nd, 2012, but has been updated to include Meryl Streep's Academy Award nomination.)