Hillary and Chelsea Clinton in Philadelphia. (AFP)

Washington, May 10: Chelsea Clinton has emerged as the key confidante her mother will consult when she makes a decision about when and how to abandon her presidential bid.

Senior aides to Clinton have told friends that they believe the former first daughter now has a vital role to play in helping her come to terms with the reality that her once “inevitable” candidacy has fallen short.

Concerned Democrats, who want Clinton to acknowledge that the electoral maths are stacked against her, have long debated the question: “Who will tell her to quit?”

The dominance of the family in the Democratic Party for two decades has left few politicians with the clout to intervene. Conventional wisdom has it that husband Bill will take her aside and issue the coup de grace because continuing may impair her chances of making another bid for the presidency in 2012.

But several of those in the upper echelons of the campaign believe that the decision would be best made in conjunction with Chelsea rather than the former President.

One senior Clinton aide told a close friend last week that Bill Clinton has too much personally invested in the campaign to make a rational judgment.

They think that explains his temperamental behaviour on the election trail, which has backfired on several occasions with claims at one point that he played the race card against Barack Obama.

The friend recalled the Clinton aide’s argument like this: “Chelsea is the key to this. Everyone has always said that Bill will be the one to take her aside, but he is too emotionally involved. You’ve seen that throughout the campaign. He’s too close to it to make the best judgments sometimes.”

By contrast Chelsea, whose role as an advocate for her mother, or surrogate in the US political terminology, has grown dramatically in recent weeks, is seen as someone with political savvy, but not a personal investment in the campaign.