The journey is long. The journey is hard. And we don't have much time left to make it. It is a journey that will require each of us to persevere through setback, and fight for every inch of progress, even when it comes in fits and starts. So let us begin. For if we are flexible and pragmatic; if we can resolve to work tirelessly in common effort, then we will achieve our common purpose: a world that is safer, cleaner, and healthier than the one we found; and a future that is worthy of our children.