John McCain spoke to Charlie Rose last week about Libya:
The Senator chose a pale green dress shirt and a muted red tie. These aren't colors we're seeing a lot of in menswear lately, but they work well for him.
White can be problematic on television in general (too reflective) and the difficulty is compounded for those with white or very light hair color, as the hair might look "dirty" in comparison to the shirt. This leads many men to choose blue dress shirts, which works fine, especially for those with blue eyes. But this green color compliments the Senator's skin tone better than a saturated French blue would, and it has the benefit of being a little bit unusual.