It appears that he was included as a member of the working group in response to pressure from activists and the media.

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In January 2009, public pressure led to the formation of a Stormont working group to explore options for non-farming rural dwellers.

BBC: Statement on planning policy

If Christie held up under the pressure, he would appeal to working class Democrats (a group where Obama is already weak) and put into play Blue states such as New Jersey, Pennsylvania and Michigan.

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