HANOVER, N.H. — In a crowded Republican field, how do you know whether your message has been effective?
When the pack turns on you. Not just the guys in the back, but he front runners as well.
"They are a little bit afraid that this long shot may not be a long shot any longer," said the Georgia Republican ahead of an eight-person contest with his rivals for the Republican presidential nomination.
It was a rare understatement from the bombastic former Godfather's Pizza executive.
Former Sen. Rick Santorum from Pennsylvania called him naÏve and said his economic plan was just opening the door for Washington to increase taxes, not a reduction as Cain promised.
Rep. Ron Paul of Texas questioned his time as a director with the Federal Reserve. Rep. Michele Bachmann of Minnesota laughed that, if his 9-9-9 economic plan were turned upside down, voters would find the devil — 6-6-6 — in the details.
And former Utah Gov. Jon Huntsman quipped the plan's name is "a catchy phrase" but not a substitute for a serious economic blueprint.
"In fact, I thought it was the price of a pizza when I first heard about it," Huntsman joked.
Cain appeared undeterred.
"I thank you very much. 9-9-9 will pass, and it is not the price of a pizza," he responded.
Cain, who has seen his popularity rise after a string of strong debate performances and a win at an early test vote in Florida, has shifted from an also-ran to a serious factor in the GOP contest. His rivals suddenly are looking at his rise in the polls with enough concern that even candidates at the front of the pack engaged him.
"I must admit that simple answers are always very helpful, but oftentimes inadequate," former Massachusetts Gov. Mitt Romney clucked during one exchange with Cain.
And Texas Gov. Rick Perry dismissed the whole plan.
"I don't need 9-9-9. We don't need any plan to pass Congress," Perry said.
Once viewed as a sideshow to the race, Cain's plain-spoken approach has provided a simpler alternative to others such as Romney.
"Can you name all 59 points in your 160-page plan?" Cain pushed Romney on his detailed economic plan.
Cain has run a nontraditional campaign. He is on a national book tour now, hawking with his latest volume. He is a frequent guest on television programs. Yet so far Cain hasn't laid the groundwork for a traditional get-out-the-vote effort in the critical early nominating states.
He shrugs off that criticism.
"And just to set the record straight: when you run for president and you move into the top tier ... you get this bull's-eye on your back," Cain said last week. "And people take pot shots left and right. But I don't want you to be unclear about where I stand on certain things."