The possibility of a rift between Sarah Palin and Michele Bachmann is something we have discussed extensively. The two have essentially the same potential base of support, so a conflict was inevitable if one didn't drop out of the race quickly. The only question is whether the feud will simmer underneath the surface, or if it will become more public.
Earlier this week, the Bachmann campaign was proud to announce that they had hired Ed Rollins as her chief campaign manager. Rollins is considered by all to be a skilled political operator. He has worked on several "insurgent" campaigns like the one Bachmann plans; Rollins managed Huckabee's almost-successful run in 2008.
Rollins quickly proved himself a potential liability. During a radio interview, Rollins made several disparaging remarks about Sarah Palin. He criticized Palin for lacking substance and quitting her job as governor of Alaska. Obviously, Rollins was attempting to contrast Bachmann with Palin, to show that Bachmann is a more serious candidate than Palin. Rollins is no doubt aware that Bachmann lacks perceived electability, and that frequent comparisons between Bachmann and the also-unelectable Palin make matters worse.
Bachmann immediately received negative feedback as a result of the story, with Tea Partiers calling on Bachmann to fire Rollins. It should go without saying that Bachmann will not fire Rollins; her campaign needs every bit of firepower it can get, and she would look weak. Bachmann did release a written statement saying that she respects and admires Palin. It remains to be seen how quickly Palin fans will get over it and support Bachmann if Palin doesn't run.
Though it appears more and more likely that Palin will not run (Bachmann wouldn't bother running if Palin was going to), the Rollins debacle highlights a real challenge for Bachmann: Contrasting herself with Palin without alienating the Palin fans she needs. Bachmann's true opponent is Herman Cain, not Palin. If Palin runs, they will split each others' support and Bachmann has no real chance anyway. If Palin doesn't run, Bachmann will need to compete against Cain.
Directly criticizing Palin is suicide for Bachmann. If she is more substantive than Palin, the phrase "show, don't tell" comes to mind. Voters will decide for themselves (largely based on debates and interviews) whether Bachmann is indeed more intelligent than Palin. They won't make that determination based on a statement from Bachmann's campaign manager.
Supposing a feud between Palin and Bachmann continues, Palin supporters will easily find their way into the Cain camp. Indeed, Palin herself could end up endorsing Cain. After all, Palin has a long history of feuding with people who cross her, and she does not forgive easily.