This is the part from a novel 'Baker's blue-jay yarn' by Mark Twain. The sentence in bold is what I don't exactly understand.
You may call a jay a bird. Well, so he is, in a measure - because he's got feathers on him, and don't belong to no church, perhaps; but otherwise he is just as much a human as you be. And I'll tell you for why. A jay's gifts, and instincts, and feelings and interests, cover the whole ground. A jay hasn't got any more principle than a congressman. A jay will lie, a jay will steal, a jay will deceive, a jay will betray; and four times out of five, a jay will go back on his solemnest promise.
Does that sentence literally mean that congressmen normally have a lot of principles to follow while blue-jay doesn't have many of them? Or is there any connotative meaning?