David Frum makes a good case that it would actually be in the McCain campaign's self-interest to tear down the wall it's erected between Palin and the media:

A question I am often asked when I give talks or lectures is: Why did the Bush communication effort end so badly? How did an administration that once commanded such public support end by losing all ability to make its case?

My answer is that the ultimate failure was encoded into the initial success. The president's communication team - of which Nicole Wallace was an important part - shared the same disdain of "elites" that permeates so much of my pro-Palin correspondence. It was not just the media elite that they disregarded. (Who could blame them for that?) It was the policy elite too. When the president wished to advocate, eg a tax cut, he did not argue his case before the Detroit Economic Club or send a surrogate to Jackson Hole. He made a rally speech before cheering supporters. That made for effective soundbites and exciting images. But it abdicated any effort to make an argument that could convince people who were not predisposed to be convinced.

At first, this abdication did not much matter. The president was popular, the public was united. But once the administration encountered trouble and adversity, it discovered - it found itself disarmed. It had no advocates other than its own in-house communicators and the most committed partisans. There were pitifully few respected independent voices ready to join the discussion on behalf of the administration's policies. They could not convince, because they had not been convinced.

Speaking directly to the people works when the people are intensely engaged. But big publics pay only intermittent attention to politics and policy. When that attention is diverted, specialists and enthusiasts reclaim their usual disproportionate impact.

By that time however the argument may well have been lost among that portion of the public that is still paying attention.

Of course, Frum is arguing that it would be in the McCain campaign's long-term self-interest to let Palin do interviews. But the mere fact that Palin is on the ticket is proof that the McCain campaign is thinking purely in the short-term right now. 

--Jason Zengerle