The path towards sustainable energy sources will be long and sometimes difficult. But America cannot resist this transition, we must lead it.

The other reason might be that you want to talk to voters when you've got seven primaries in seven days. Understand what's happened in this race - where we campaign actively in a state, and voters have the chance to see me directly, they check under the hood, and they kick the tires, when we don't have as much time.

Tonight, let us think back to the sense of unity that prevailed on 9/11.

Reading is important. If you know how to read then the whole world opens up to you

I don't believe we can get very far, with leaders who write off half the nation as a bunch of victims who never take responsibility for their own lives.

It's the reason why I am always interested in engaging in people who are pushing us and pushing against the status quo. But having been an activist, the only thing that I'm always encouraging activists to do is, once you have raised the issue, and even through controversial means, you have to come behind it with an agenda and the possibility of reconciliation if power meets your demands.

As an elected official who comes from the African-American community, there are some similarities. You are always trying to reconcile your own personal biography and affiliations with the demands of the broader democracy. And you need to make sure you are representing everybody.