My first reaction to Pres-elect Trump giving "alt-right" [for lack of a better term] Breitbart boss Steve Bannon a top slot—even if more symbolic than substantive—was that he's determined not to let his right flank slip, and indeed turn and rend him.
Jimmy Carter's biggest political failure was losing control of his own party, and as Douglas Brinkley fascinatingly chronicles here,* it was Carter's disaffected left flank that did him in more than Ronald Reagan.
I don't know if Trump [or his advisors] learned from history, but so far at least he just avoided a major snare—losing your own side without whom you cannot hope to lead or govern. That and hiring GOP chair Priebus as Chief of Staff—Reince knows all the players: Keep your friends close and your enemies closer.
*"Tales of Carter's contempt for and ineptitude at politicking were legion on Capitol Hill throughout his term in office. "When it came to the politics of Washington, D.C., he never really understood how the system worked," Tip O'Neill wrote in his memoirs. "And although this was out of character for Jimmy Carter, he didn't want to learn about it either." In fact, O'Neill couldn't escape the feeling that Carter was working against fellow Democrats--including the Speaker himself. "Once, when the city of Boston applied for a government grant for some roads, I called the Carter people to try to speed it along," O'Neill wrote. "Instead of assisting me, however, they did everything possible to block my way."
Other perceived slights were more subtle..."