That was the lesson your grandmother tried to teach me when I was your age, reading me the opening lines of the Declaration of Independence and telling me about the men and women who marched for equality because they believed those words put to paper two centuries ago should mean something.

She helped me understand that America is great not because it is perfect but because it can always be made better—and that the unfinished work of perfecting our union falls to each of us. It's a charge we pass on to our children, coming closer with each new generation to what we know America should be.

I hope both of you will take up that work, righting the wrongs that you see and working to give others the chances you've had. Not just because you have an obligation to give something back to this country that has given our family so much—although you do have that obligation. But because you have an obligation to yourself. Because it is only when you hitch your wagon to something larger than yourself that you will realize your true potential.

These are the things I want for you—to grow up in a world with no limits on your dreams and no achievements beyond your reach, and to grow into compassionate, committed women who will help build that world. And I want every child to have the same chances to learn and dream and grow and thrive that you girls have. That's why I've taken our family on this great adventure.