Scott Olson / Getty Images Tea Party members rally to protest President Barack Obama's proposed "Buffett rule" tax plan on April 16, 2012 in Chicago, Illinois.

Senator Alan Simpson became the latest Republican to confront the Tea Party last weekend when he said on CNN, “If you want to be a purist, go somewhere on a mountaintop and praise the east or something. But if you want to be in politics, you learn to compromise. And you learn to compromise on the issue without compromising yourself. Show me a guy who won’t compromise and I’ll show you a guy with rocks for brains.”

The fear-based purism of the Tea Party brings to mind the developmental phase we see in toddlers who insist on keeping separate the different foods on their dinner plate: in their quest for certainty, a fleck of green parsley in their plain spaghetti will ruin the entire meal. The extremist drive for political absolutism is driven by a similar fear of contamination.

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On a different psychological level we see a fear of being force fed – that the mother or father is going to make the child eat the spaghetti despite that speck of parsley. This perspective equates compromise with surrender, a recent theme in primary races with Tea Party candidates. Recently, Indiana Republicans defeated long-time stalwart senator Richard Lugar in favor of a man who promised never to compromise with any Democrat. Texas Tea Party Senate candidate ran ads portraying his Republican opponent as a “moderate,” meaning he’s someone willing to work across the aisle.

This anxiety is also expressed in adulthood as the fear of having to mix with people who are different from self. A high percentage of the Tea Party extremists to whom Simpson refers still can’t accept someone as different from them as Obama as their president. And what goes far beyond a simple bit of parsley is that Obama is experienced as a living, breathing contaminant that threatens to force-feed his other-ness down the throat of America.

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Simpson describes the problem but not the cause— the real fear of the “other” that motivates the purists he identifies in his party. This fear is not new; we experience it individually as the fear of being controlled, or of having things taken away. These fears have been central to American history since the founding of the nation. But we no longer have wide open spaces to which we can run from our fears; we now must acknowledge and put them in perspective so they won’t continue to block progress and growth.