And with iPods and iPads, and Xboxes and PlayStations - none of which I know how to work - information becomes a distraction, a diversion, a form of entertainment, rather than a tool of empowerment, rather than the means of emancipation.

The incredible story of progress that is America has always been built by those who ask why, what if, and why not. Our schools must begin instilling that wonder in our children again so that their generation will unite around the next great project of our time, whether it be declaring America energy independent or launching the next great technological revolution.

His peaceful resistance shook the foundations of an empire, exposed the emptiness of a repressive ideology, and proved that moral leadership is more powerful than any weapon.

Here's the truth: even if countries like the United States curb our emissions, if growing countries like India - with soaring energy needs - don't also embrace cleaner fuels, then we don't stand a chance against climate change.

Together we can change our culture for the better by ending violence against women and girls, artists have a unique power to change minds and attitudes and get us thinking and talking about what matters, and all of us, in our lives, have the power to set an example. Join our campaign to stop this violence.

There's no question that a lot of Americans on both the right and the left are expressing some fears and frustrations about the dislocations brought on by globalisation. Many of those frustrations are legitimate and they need to be addressed.

While we have come a long way since the Stonewall riots in 1969, we still have a lot of work to do. Too often, the issue of LGBT rights is exploited by those seeking to divide us. But at its core, this issue is about who we are as Americans. It's about whether this nation is going to live up to its founding promise of equality by treating all its citizens with dignity and respect.