I think that the root of your redundancy problem (and you're right to identify that as a problem) is that your argument isn't moving towards anything at the moment. You are basically applying the same concepts with different examples from paragraph to paragraph. This makes me as a reader feel like you're never really going to get to the point of all of this. What I recommend changing is your organizational structure.
Here are some questions that I suggest you consider:
What is it that I want to argue? Am I arguing that politicians use rhetoric that depends on verb tense, or am I arguing that there is an effective way to do this? Is there a particular piece of rhetoric that I prefer because of its well-craftedness (with regard to verb tense)?
If you are merely arguing that this technique is utilized, then you accomplish it pretty much in the first body paragraph. If you are trying to discuss how well the technique is utilized, you should build towards that with the structure of your paper.
The teacher in me is pretty reluctant to throw down the outline that I would use, because that is neither good instruction nor good "peer review." You've got to figure it out for yourself. But I'm glad to talk you through it if you're interested.