The question I have been asking myself and others during my entire life in public policy and throughout this 2008 presidential Campaign — the question which tens of millions of women and men have also been asking — is how do we best bring America together in shared purpose, prosperity and, especially, equality.

Those of us who until last week worked for Senator John Edwards to become president were always fighting for something bigger than any of us and bigger than all of us. We were also part of a movement with the objective, John's objective, of lifting up all Americans.

John Edwards is not going to be president, and so what we who were helping him must do is now elect the individual who has deep in his core John's principles and vision for this country. And so today, with every ounce of passion and enthusiasm I have, I am endorsing Senator Barack Obama to be president of the United States

Barack Obama is also calling our nation to the greatness that we all want but that we're uncertain we can still achieve. Others talk about greatness and they even say all the right words, but they do not bring those words to life. Their words do not grab us by the arms and pull us along together.

Barack Obama, like John Edwards, is redefining what is possible and in so doing he's changing us, each one of us.

Many who had given up on politics are re-engaging. Many who had grown tolerant of the intolerable are now ready to demand more ­ and not just from themselves but others. And many who had given up believing that the ideals of equality, dignity and justice would ever again be as politically important as money and power, now believe again.

And this too is why I'm endorsing Senator Barack Obama.

Barack and John Edwards were different candidates, with different backgrounds and life experiences, but all these many months and really throughout their lives, they have been on a common path.

Both are focused on changing our politics, both are committed to shaking the foundation of the Washington establishment, and both are profound voices for what our country should and can be.

When I endorsed John Edwards for president, I did so because I was confident he would help lift women out of poverty and protect a woman's right to make her own decisions about if or when to have a family. I was confident that if John were in the White House, the single mother, who was working two jobs, living paycheck to paycheck, and worried about health care and child care, would have more influence than the well-healed corporate CEO armed with a team of lobbyists.

And when I endorsed John Edwards I also knew that Barack Obama shared every one of these concerns, and over the course of Barack's own campaign, the nation has come to believe in him just like I always have as well.

Senator Obama is not just prepared to lead ­ as our beloved Teddy and Caroline Kennedy have said, he is prepared to lead in a way different than we have seen for decades. Not out in front with us behind him, but rather with us beside him.

And that difference is all the difference. That difference separates just any president from a great president; and right now, we need a great president.

Barack Obama will be that great president. He will bring us all together. And together, we will change our country.

During these past many years, we have lost the sense of what we could do together, who we could be, what was possible.

That's changing.

And Barack Obama is the one changing that.

With him, greatness is again within reach.

This article was originally published on The Huffington Post.