U.S. first lady Michelle Obama (L) greets former first lady Laura Bush as they participate in the "Investing in Our Future" forum at the US-Africa Leaders Summit in Washington Aug 6, 2014.[Photo/Agencies]

Obama, 50, married a fellow lawyer who went onto great heights. And yet neither seems especially enamored of politics, and each has carefully tailored her public role to suit her own priorities and tastes.

Their mission, of course, is not especially controversial in the US political context, and so it is easy ground for them to make common cause. Bush spent much of her husband's administration trying to help women in Africa, Afghanistan, Myanmar and elsewhere, and has continued such projects at the George W. Bush Institute in Dallas.

Obama this year started her own initiative, Reach Higher, and has been sharing her personal story to inspire girls and young women around the world.

"You have to change attitudes before you can change behaviors," Obama said during the discussion at the Kennedy Center, moderated by Cokie Roberts of ABC News. "Until we prioritize our girls and understand that they are as important and their education is as important as the education of our sons, then we will have lots of work to do."

"My hope," she added later, "is that I can start a national conversation about reigniting that hunger for education in our young people, and using that to talk about the issues that our girls around the world are facing."

The two first ladies traded lessons from life under the most intense scrutiny in the world. Bush brought her husband, who later addressed the same forum to promote efforts to combat AIDS, cervical cancer and breast cancer in Africa. But he stayed off stage as the fi rst ladies talked, with Laura Bush saying she had the advantage of seeing up close the impact of presidential life on her father-in-law and mother-in-law before moving into the White House herself.