Example of Group Dynamics in Obama’s speech on race

It’s obvious; “race” is an issue in this US presidential campaign. If Obama win this election, then he turns a new page in American history for that being the first black American president. So, how does he deal with this issue? In this speech,”A More Perfect Union” he made on March 18, he appealed to a union of different races in this country. He used the “Group Dynamics” language trying to build a sense of solidarity.
Searching for this speech, please go to www.video.google.com, then search” Obama speech”, there are lots of speeches.