This visit [to Singapore] is an occasion to mark the 50th anniversary our bilateral relationship with Singapore, which is one of our strongest and most reliable partners in South-east Asia.

Let's remember that our leadership is defined not just by our defence against threats, but by the enormous opportunities to do good and promote understanding.

The people there, the community, the lessons that I learned -- they're all based right in this few square miles where we'll now be able to give something back and bring the world back home after this incredible journey.

Even the smallest act of service, the simplest act of kindness, is a way to honor those we lost, a way to reclaim that spirit of unity that followed 9/11.

Now, the Iranian people are a great people, and Persian civilization is a great civilization. Iran has acted in ways that's not conducive to peace and prosperity in the region: their threats against Israel; their pursuit of a nuclear weapon which could potentially set off an arms race in the region that would make everybody less safe; their support of terrorist organizations in the past - none of these things have been helpful.

Hope is not blind optimism. It's not ignoring the enormity of the task ahead or the roadblocks that stand in our path. It's not sitting on the sidelines or shirking from a fight. Hope is that thing inside us that insists, despite all evidence to the contrary, that something better awaits us if we have the courage to reach for it, and to work for it, and to fight for it. Hope is the belief that destiny will not be written for us, but by us, by the men and women who are not content to settle for the world as it is, who have the courage to remake the world as it should be.

Today, about 40 percent of America's carbon pollution comes from our power plants. There are no federal limits to the amount those plants can pump into the air. None. We limit the amount of toxic chemicals like mercury, and sulfur, and arsenic in our air and water, but power plants can dump as much carbon pollution into our atmosphere as they want. It's not smart, it's not right, it's not safe, and I determined it needs to stop.