Gingrich generally does that in order to frame his answer based on contextual historical facts. The others just prattle on with little or nothing to substantiate their responses.
One very simple example is the following video clip when an MSNBC reporter interviewed Gingrich and made an unsubstantiated comment regarding Palin:
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Newt Gingrich destroys MSNBC reporter
http://www.youtube.com/watch?v=YsUw2Vq8UMw&feature=related
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Could anyone else, including Palin herself, respond as simply, factually, and succinctly as Gingrich did in the above clip? And turn the tables on the foolish reporter who was incapable of answering Gingrich's question at the end of the interview?
This is why Gingrich can defeat Obama (with or without his teleprompter).
That was one of my favorites. ;>)