People close to the campaign echoed Mr. Rollins. They spoke of their frustration that Mrs. Bachmann, who entered the race with a reputation for making unsupportable statements on cable television, has not found the discipline to win credibility with major Republican donors and influential referees in the conservative news media.

The Wall Street Journal’s editorial page, for one, accused her of “vaccine demagoguery.”

Jim Dyke, a former communications director for the Republican National Committee unaffiliated with any candidate, said: “This is the nail in the coffin in her campaign. Because you can be a cable television darling by saying provocative things, but you can’t be president of the United States.”…

People close to the campaign, who spoke on condition of anonymity, said Mrs. Bachmann is often influenced by the last person she speaks with on an issue rather than maintaining discipline in communicating a message.