"Learn how to craft an effective character reference letter for court proceedings with our comprehensive guide. A character letter is designed to show support for a defendant in a criminal case.These letters have the potential to influence the court. A character letter to a judge should establish your credibility, paint a full picture of the defendant and be respectful, among other things. How To Start Your Letter. Everything you need to write a declaration letter to the judge in your custody case: an example, a downloadable template, an outline and tips.