"The politicians were talking themselves red, white and blue in the face"

This quote is an amusing way of saying that the political leaders were talking a lot. It implies that they were talking a lot that their faces were reddening, white, and blue, the colors of the American flag. This might be translated as a criticism of the politicians for talking excessive and not taking action. It could also be translated as a sign of patriotism, as the politicians are so passionate about their beliefs that they are talking themselves into a patriotic fervor. Either way, the quote indicates that the political leaders were yapping which their words were having an effect on them.