"And we've demonstrated the importance of American leadership - and American partnership - on behalf of our own security, and the world's."

VOA: standard.2010.04.04

I think what we do in America whatever people might say about we're on a way up or we're on a way down, we still have vast power in team influence on what's going in this world Absolutely. -with the kind of financial and leadership role.

我认为我们在美国所做的,无论人们如何评价,我们在前进或在倒退，我们仍然拥有巨大的力量,对于世界的发展有着极大的影响,绝对是，-因为我们拥有巨大的金融实力,以及领导作用。

普林斯顿公开课 - 人性课程节选

"It is absolutely imperative that America takes leadership, working with not just our Russian counterparts but countries all around the world, to reduce and ultimately eliminate the dangers that are posed by nuclear weapons,"

VOA: standard.2009.05.19

And so the G-20 meeting, where leaders representing 80 percent of the world economy will be present, is an extraordinary opportunity for Obama precisely to show the U.S.leadership that he has been talking about,".

VOA: standard.2009.03.31

So I think that those two things kind of together, her own perspectives on the world, her lack of relationships on the other side have made for a divisive kind of leadership, that has come out of the House.

VOA: standard.2010.05.11

He's also decided to give up leadership in Light up the World Foundation to start a company in India that will develop a more energy-efficient and cheaper lighting system that he hopes will bring even more light to the world's poor.

VOA: standard.2009.12.13