It is logos.
The excerpt from the Declaration of Independence uses logical arguments to persuade.
The Logos concerns the content of discourse, the use of logic. That is, to the way the thesis is presented, the clarity of the discourse, the use of techniques such as repetition, the careful choice of the order of the arguments and the strength of its arguments, reducing the hypotheses of refutation.
The logos suggests that your speaking in public will not be convincing if you can not logically prove what you are saying which makes sense, although this is not the preponderant factor for the success of your presentation.