Washington (CNN) - Several unaffiliated Republican operatives say Herman Cain must say more about the sexual harassment allegations being leveled against him, because his current message is not putting the controversy to rest.
"He needs to be upfront, forthright and get this story behind him," Bob Vander Platts, a leading Iowa Republican activist, tells CNN. The ongoing allegations, he adds, are a "test of Cain's leadership" and "a tipping point for his campaign."
Both Vander Plaats and a national Republican activist who requested anonymity said Cain's dual message of attacking the media - and not answering more detailed questions about the four women who have come forward accusing him of inappropriate behavior when Cain headed the National Restaurant Association - is fueling more controversy.
This operative, who didn't want to speak on the record in order not to upset the Cain campaign, said the issue could especially hurt him with women who are an important part of the Republican primary electorate.
Cain has vehemently denied he sexually harassed anyone, and late Monday his campaign sent an e-mail to supporters in his name lashing out at the media.
"Once this kind of nonsense starts, the media's rules say you have to act in a certain I am well aware of these rules. And I refuse to play by them," Cain states.
In the message, Cain does not respond to the specific allegations former National Restaurant Association foundation employee Sharon Bialek makes against him. Instead, he talks about people who will not give their names and witnesses who won't give their names.
"That's about what you would expect when people are engaging in a 'hatchet job," Cain says. "If the media want to continue talking about nonsense, that's fine. I'm not going to join them. It doesn't like the citizenry plans to join them."
Iowa's Vander Plaats says the Republican activists in the state are fair and will not rush to judgment but will need more information.
"If it's true, he's got huge problems," Vander Plaats said. But if it's not, then Cain needs to provide more information in order to clear the air, he said.
"It goes at the question of character and integrity and can I trust you," he added.
"You cannot let this dominate the campaign," Vander Plaats said, a sentiment echoed by other analysts. He said Cain can "approach this with humility and sincerity" and people will listen. "Iowans are fair."
Cain will be in Iowa on November 19 for an event sponsored by Vander Plaats called the Family Leader Forum. An expected 2,500 potential caucus-goers will be in attendance, and Cain will surely have to address the issue in some form.
In a column on CNN.com, Republican strategist and CNN contributor Bill Bennet writes that Cain needs to address the charges.
“If Herman Cain cannot stand up to these charges, if he refuses to, then he should step out of the race," Bennett writes. "A man big enough to run for president should be big enough to have a full and candid press conference on all of this–he wants us to elect him President after all, he's asking us to trust our lives and the country's life to him. This could be one of his finest moments and it could be one of his worst. But either way, he must confront the moment candidly and manfully.”