Editor’s Note: ABC News Correspondent Cokie Roberts discusses her bestselling new book Ladies of Liberty: The Women Who Shaped Our Nation.

LESLEY: You know, we tend to think there was no really influential first lady until Eleanor Roosevelt.

COKIE: Well, we would be wrong.

Click here to read Part Two: Who Was John Adams’s Political Compass? His Wife Abigail, Of Course.

Click here to read Part One Cokie Roberts: Eliza Hamilton, the Silda Spitzer and Pearls Behind Swine of Her Day.

Click here to read Part Four: First Ladies Throughout History Have Just ‘Done What Women Do; Whatever’s Needed, Whenever That May Be.’

LESLEY: We would be wrong. You come along, you write this book and tell us what some of us sort of suspected — that Dolly Madison was the “Presidentess,” as you said, and an enormous center of power.

COKIE: Oh, she was. And she was a terribly important one for the sake of the nation because this was a time when people were just at each other’s throats. They were literally killing each other over politics. Those duels were fought over political words. And Thomas Jefferson, as president, only entertained one party at a time. So the partisanship just grew and grew. And Dolly Madison made these people come together and sit down and talk to each other and behave, and try to abate the partisanship that could have torn the country apart.

LESLEY: Which she succeeded at, to some extent.

COKIE: She did. And she certainly succeeded in getting her husband elected. I mean his first opponent said, “I was beaten by Mr. and Mrs. Madison. Had I just run against Mr. Madison I would have had a better shot.” And in his second election, James G. Blaine, the politician historian, wrote, “The administration of Mr. Madison was saved by Dolly Madison. But for her, DeWitt Clinton would have been elected president in 1812.” So she not only was good at it, she got credit for it.

LESLEY: Yeah.