Your case theme can have a major impact on the trier of fact. When you develop a powerful case theme, you give the trier of fact, a lens through which they will view the evidence in your case. Your opening statement, your witnesses and their direct examination, the evidence you submit, your cross examination should relate the your case theme and sub-themes in your case. These will sum up in your closing arguments to the trier of fact. 
The trier of fact, will start looking for the evidence that supports your case theme that you told them in opening argument. That is why it is so important to invest time developing your case theme. The better your theme “hooks” the trier of fact, the more likely you are to win. 
Taglines, catch-phrases, and themes have a powerful persuasive effect in the courtroom. Invest some time developing your theme, and then try it out outside the courtroom. Share them with your colleagues and staff, your friends and family, etc. The important point is to refine your theme until it captures the essence of your case, giving the trier of fact a compelling lens through which to view the trial.