One close associate of the former president, speaking on condition of anonymity to avoid a personal confrontation with the governor, warned Mr. Perry against establishing his own conservative bona fides by criticizing Mr. Bush, saying, “If you’re really trying to be the nominee and want to go the distance, you just don’t want the former president of the United States and his people working against you.” Another, speaking anonymously as well, said, “He’s going to need all the help he can get from all the Republicans he can muster, so he ought to be prudent about that.”…

Neither Mr. Bush nor Mr. Perry would be interviewed for this article, and people close to both said the rivalry existed far more between their aides than between them personally.

The relationship between the camps includes a rich mix of political differences, class distinctions, loyalty questions and perceived slights of campaigns past. And it is a uniquely Texan story, opening in the Western dust bowl where both emerged — Mr. Perry as a conservative Democratic state lawmaker from a modest farming family, Mr. Bush as a failed Republican Congressional candidate of famous New England stock…

The tensions first spilled out publicly in 2007, when a video wound up on YouTube capturing Mr. Perry speaking dismissively of Mr. Bush during a Republican house party in Iowa for former Mayor Rudolph W. Giuliani of New York. In the video, Mr. Perry said, “George Bush was never a fiscal conservative — never was,” adding, “I mean, ’95, ’97, ’99, George Bush was spending money.”

Unhappy Bush aides noticed.