Politicians are just like the rest of us. They find it hard to do the right thing. They claim to have principles, but when their principles clash with what is expedient, they often find a way to justify their self-interest. If they sacrifice what is noble or ideal for personal gain, they are sure to explain that it was all for the children, or the environment or at least for the good of society.And yet voters are stupid enough to be fooled.
Pigs don't fly. Politicians, being mere mortals like the rest of us, respond to incentives. They're a mixture of selfless and selfish and when the incentives push them to do the wrong thing, albeit the self-interested one, why should we ever be surprised? Why should be fooled by their professions of principle, their claims of devotion to the public interest?
Roberts makes a nice point about bootleggers and Baptists,
The Baptists give the politicians cover for doing what the bootleggers want. No politician says we should ban liquor sales on Sunday in order to enrich the bootleggers who support his campaign. The politician holds up one hand to heaven and talk about his devotion to morality. With the other hand, he collects campaign contributions (or bribes) from the bootleggers.