Arnold Kling sounds almost cynical:
The main science of political economy is the science of obtaining and retaining power. As far as expertise goes, the pollster, the fundraiser, and the media expert are all fundamental to the operation. The public policy expert is for decoration. If you want to be an economic policy adviser when you grow up, then my advice is to learn to rationalize the methods used by leading politicians to obtain power.
Well, that might be good for the spleen, but there’s another way of looking at it. I am referring to Bentley’s "Process of Government" theory. Bentley’s theory sees politics as "a never-ending, small-bore struggle for advantage among constantly shifting coalitions of interest groups". Seen in that light, politicians are best seen as power brokers who attempt to navigate through the small-bore struggles while maintaining popularity. This is a more sympathetic view of politicians that neither raises false hopes nor paint the process in the darkest colors. That’s just the way it is and, however unsatisfying, the way it has to be. There’s no more point in being outraged about political behavior than there is being outraged by a thunderstorm.