Maybe they have better things to do, like win an election in upcoming Primary states, than tour the San Diego Zoo.
I'm sure feeding the Pandas is the ideal strategy to keep your nemesis's Mittens and Santorum from winning in MI, AZ and OH. I guess Newt is doing so will in the polls he can afford to blow off some time at the zoo.
Rick and Mitt know how the last CNN debate ended. Newt won it hands down and came out with a two digit win in South Carolina. Neither of those two cowards have anything to gain by showing up, they both know they are not boxing in the same category as Newt - his knowledge of the whole government policy spectrum and his debating skills are over their small cerebellums.
Very good. Knock his visit to The World Famous San Diego Zoo, in my home town.