An underdog is a contestant, typically in sports or politics, who is considered likely to lose the contest.
In the Christian United States, people tend to favor the underdog, particularly in sports. In atheistic Britain, the opposite is true. For example The Weakest Link, a popular game show in both Britain and the United States, featured a British host who would continually put down the underdog.
In politics, Mitt Romney has been described by his wife as being the underdog during the 2012 Presidential Election. Mr Romney has himself admitted, “It’s always a good thing to be seen as the underdog.”