Why is John Edwards still running? When is he going to face reality and throw in the towel?Even Edwards' friends are asking these questions after his poor showing in the Nevada caucuses, which followed disappointing results in Iowa and New Hampshire, and with polls predicting a distance third place in this week's South Carolina primary.What are Edwards' answers?To the question of when he will quit the race, Edwards recently said, "I'm in this for the long haul. I will be in it through the convention and to the White House and so I have a very long view about this."His campaign organization said it this way after Nevada: "The race to the nomination is a marathon and not a sprint, and we're committed to making sure the voices of all the voters in the remaining 47 states are heard. The nomination won't be decided by win-loss records, but by delegates, and we're ready to fight for every delegate."To the question of why he is still running, Edwards' answer is simple: "I intend to be the nominee."Some of his supporters believe he still has a chance if he will stay in the race. One of them gave a "likely scenario" for Edwards to become the Democratic nominee. After the Super Tuesday (Feb. 5) primaries, the supporter explains, one of the two leading candidates, probably Obama, who will have lost most of the contests, will drop out. "And this is where an opportunity arises for John Edwards. ... If John Edwards decides to stay in the race, even with a relatively small number of delegates, and challenges Clinton in the remaining states -- of which there are dozens -- he may pick up many of the former Obama supporters. And the race will get interesting again."Interesting, but most political observers would say, unlikely.If his chances of winning have evaporated, why then would Edwards stay in the race?It's ego, says one of Edwards' harshest critics, commentator Lawrence O'Donnell. "Nothing but egomania keeps Edwards in the race now. All presidential candidates are egomaniacs but some of them have party status worth preserving that forces them to drop out when they hit the wall. A loser like Edwards has no status or dignity to lose. Campaigning and losing is his life."Actually there are several positive reasons Edwards may want to stay in the race, including keeping hold of the "bully pulpit" he has earned as a serious presidential candidate. Even if Edwards runs a distant third in every one of the upcoming primaries, he will have a place in the debates and an opportunity to showcase issues that he thinks are important for the country to address. Once he drops out, he can still comment on issues, but it will be much harder to get an audience. In short, there is no reason he should give up his hard-earned place as the third candidate on the Democratic primary platform to Dennis Kucinich.One person close to Edwards suggested another reason Edwards should not withdraw, explaining that Edwards will be winning a few delegates in almost every primary. They will add up. It is possible that neither Clinton nor Obama will have enough convention votes to win the nomination without support from Edwards' delegates. In that case, Edwards could have a tremendous influence on the outcome of the convention, the campaign platform of the winner, and an opportunity for Edwards to serve in an important capacity should the Democratic nominee win in November. I bet there is another reason Edwards is not quitting yet. He grew up in North Carolina playing sports like many of the rest of us. Our parents and our coaches tried to teach us rules of good sportsmanship, including how to act when we won and when we lost. Good sports never quit in the middle of the game, no matter how badly they were getting beat. They play their hearts out until the end of the game. They run the race to the end, even if the winner has already crossed the finished line.Remember what they told us? "Quitters never win, and winners never quit." Maybe John Edwards remembers, too.