What do I tell the student in response to a request for graduate school recommendation from an otherwise-qualified student who cheated by copying homework in one of my classes? I am unwilling to write a strong recommendation for this student, based solely on the episode of misconduct. If it hadn't happened, I'd recommend him strongly.
Edit: I was searching for something less blunt than "no" and something a bit less accusative than "no because you cheated." With the help given below, I've decided on the following:
While every recommendation letter I write is tailored to the particular student, all include comments on each of those things I believe are relevant to admissions committees. One of those is academic integrity. In your case, a comment from me on academic integrity would likely be fatal to your application. For that reason, I must decline to write such a recommendation. I am confident that you can find professors who can write strong recommendations, and I wish you the best in the future.
Edit: The question identified as a possible duplicate whether whether the professor is obliged to write a recommendation for the student who cheated. My question is about the best way to decline.