As a nuclear power - as the only nuclear power to have used a nuclear weapon - the United States has a moral responsibility to act.

Change is never easy, but always possible.

I believe that this country succeeds when everyone gets a fair shot, when everyone does their fair share, when everyone plays by the same rules.

That we are in the midst of crisis is now well understood. Our nation is at war, against a far-reaching network of violence and hatred. Our economy is badly weakened, a consequence of greed and irresponsibility on the part of some, but also our collective failure to make hard choices and prepare the nation for a new age. Homes have been lost; jobs shed; businesses shuttered. Our health care is too costly; our schools fail too many; and each day brings further evidence that the ways we use energy strengthen our adversaries and threaten our planet.

In the wake of 9/11, my meetings with Arab and Pakistani Americans, for example, have a more urgent quality, for the stories of detentions and FBI questioning and hard stares from neighbors have shaken their sense of security and belonging. They have been reminded that the history of immigration in this country has a dark underbelly; they need specific reassurances that their citizenship really means something, that America has learned the right lessons from the Japanese internments during World War II, and that I will stand with them should the political winds shift in an ugly direction.

Each wave of immigrants that have come in have been able to assimilate, integrate and then rise up and become part of this great American Dream.

We could come together, Democrats and Republicans, to find practical, commonsense solutions to health care, to education, to energy issues, because although I'm a proud Democrat, I'm a prouder American. And I think all of us believe, regardless of our party affiliations, that this is a critical time, where we've got to solve big problems.