The two "we"s in this example all referred to the Democratic Party. The opinion expressed in this example is the decision made by the whole party. Obama is only a speaker to deliver this decision therefore he is by no means subjective. What’s more, "we" is an ambiguous word, from which we cannot find any exact person who should be responsible for the actions mentioned in the example. That is to say Obama reduced skillfully the responsibilities that should be put on his shoulder.

Example 6: for even as we celebrate tonight, we know the challenges that tomorrow will bring are the greatest of our lifetime–––two wars, a planet in peril, the worst financial crisis in a century. (extracted from This Is Your Victory: Election Night)

Obviously, "we" here includes both Obama and the audience. A talented speaker must know the importance of interacting with his audience. The use of "we" is an ideal method for it efficiently shortened the distance between the speaker and the audience. After hearing the example above, the audience unconsciously think what the speaker think and feel what the speaker feel.

According to statistics, "we" is the most frequently used personal pronoun in Obama’s speeches. Although "we" is the plural form of "I", it has both single and plural meaning. Linguistic scholars separate the use of "we" into two parts. One is "we-inclusive-of-addressee" and the other is "we-exclusive-of-addressee". In speeches, the "we-inclusive-of -addressee" is the most widely used. All the examples analyzed above use the inclusive "we". No matter the word "we" refers to the American citizen, the US government or the audience and the speaker, Obama is always counting himself in. He was never been rich nor had a prestigious status, therefore, he understand thoroughly the worries of the ordinary Americans. He values the intimacy between the common people and himself, and he needs their support. "We" in his speeches showed his determination of changing the present America into one that is really equal to any American people.

2.3 The Use of "You"
The word "you" can be the singular or plural form of the second person pronoun. Different context can vary the referents. Generally speaking it can refer to inpidual listeners as well as the opponent of certain idea. Considering the use of person pronoun, the distance between the speaker and the second person pronoun is longer than that between the speaker and the first person pronoun. Mostly, the aim of using "you" is to refer to speaker’s opponent or provoke thinking among the hearers.

Example 7: You want a fight, President Bush? Let’s finish the fight with Bin Laden and al-Qaeda, though effective, coordinated intelligence, and a shutting down of the financial networks that support terrorism, and a home-hold security program that involves more than color-coded warnings.(extracted from Speech Against the Iraq War)

As is said before, the word "you" can mean anyone who fights against the idea of the speaker. In the speech against the Iraq War, Obama respectively asked "you want a fight, President Bush" at the beginning of four continuous paragraph. By asking in such strong and direct tone, Obama sharply denounced the incapability of the Bush government. At the same time, he indirectly showed his clear determination to build a better nation for the public. Obama asked not only for himself but also for the ordinary American people. The audience will have the feeling that what Obama had said is exactly what they want to say to President Bush.

Example 8: Because while John McCain thinks this campaign is all about me---the truth is, this campaign is about you. It’s about your jobs. It’s about your health care. It’s about your retirement. It’s about your children’s future. (extracted from Financial Crisis Requires Action) 浅谈奥巴马演讲中的语用策略(6):http://www.youerw.com/yingyu/lunwen_1567.html