Republican presidential candidate Herman Cain, already knocked off his message by allegations of sexual harassment, has told campaign aides he now needs to decide whether his campaign has been damaged beyond repair by a new claim that he had a 13-year extra-marital affair.
Mr Cain has vehemently denied all the charges but said - in a conference call with campaign staff - that the allegations of the long affair with 46-year-old Ginger White had created a political "firestorm".
The former executive of a pizza restaurant chain said he needed to decide if the latest allegations by Ms White "create too much of a cloud" to continue with his bid for the Republican nomination.
Mr Cain is one of eight candidates hoping to become the party's choice to challenge President Barack Obama next year.
He surged into the top tier of candidates but has slowly slipped back in polling since allegations became public last month that he had sexually harassed or groped three women when he ran the National Restaurant Association in the mid-to-late 1990s. The trade group paid settlements to two of the women who had worked there.
Should he leave the race, the already topsy-turvy Republican nominating battle could become even more chaotic as the seven other candidates scramble for the backing of Cain supporters with five weeks remaining before the first of the state-by-state contests to choose next year's nominee.
Mr Cain shot to the top of the Republican field in late September and early October with his folksy style and flat tax reform programme. But he was never seen as the likely nominee and his support began to crumble after publicity about alleged sexual harassment surfaced a month ago. He also stumbled badly on important questions about US foreign policy.
"If a decision is made, different than to plough ahead, you all will be the first to know," he said, according to a transcript of the conference call made by the conservative magazine National Review, which listened to the conversation.
Mr Cain stuck to his topic - defence spending - in his first public speech since the allegations of the extramarital affair surfaced. He addressed an audience at Hillsdale College in Michigan, calling for investment in the military rather than cuts.
Steve Grubbs, Mr Cain's campaign chairman in Iowa, said the candidate declared that Ms White's claim had "taken an emotional toll on his family, but he's moving ahead with the campaign".