Sarah Palin jokingly calls Texas “Alaska’s little sister state,’’ but its governor--and her political ally--Rick Perry could be a big obstacle to her own potential White House run.

While the breakout performance by Rep. Michele Bachmann at Monday’s GOP presidential debate has set off speculation that the Minnesotan could usurp Palin as the favorite of Republican tea party activists and religious conservatives, Perry's announcement that he's taking a second look at a White House run sets up an intriguing potential showdown between two politicians who, up to now, have had an unusually warm relationship.