They say they don't want to complicate an already difficult diplomatic dance with Khartoum.

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If he doesn't name a conservative, that could complicate his already strained relationship with conservatives from across the country, which could spell trouble if Christie decides to run for the 2016 GOP presidential nomination.

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Their reasoning was that this would complicate payments, slow service and annoy customers who weren't accustomed to credit card-only sales on airplanes.

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