Recommendation Request and Academic Misconduct

If you are willing to strongly recommend the student for graduate study, despite his past cheating offense, then tell the student you are willing to write the letter, and then write the letter.

Otherwise, tell the student you are unwilling to write the letter, and then don't.

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Your edit clarifies that you are unwilling to write a strong recommendation letter, because of the student's past academic misconduct. I suggest telling the student, "I am unwilling to write you a strong recommendation letter, because of your past academic misconduct."

I'm gonna write an answer picking up on mkennedy's comment.

"If it hadn't happened, I'd recommend him strongly."

Okay, you get to think about why you'ld recommend him strongly, if this homework copying hadn't happened. Is he/she that good (from other work that you have seen) that, not only the student, but the department the student is heading for would be better off with him/her than without?

In a previous answer to a similar question I recommended to the prof to:

1. Talk to the student. (I would have done this the moment he/she approached for a recommendation.)
2. Warn the student that the recommendation might include this incident (including any positive outcomes), but maybe not.
3. The prof needs to search his/her own soul about "crime and punishment" or "infraction and redemption" and how he/she feels about the student's rehabilitation,
4. and, independently of the incident, the prof needs to search his/her own head about this student's performance in your discipline.
5. Ultimately this prof needs to decide whether or not the cosmos would be better off writing the letter or not. That is not synonymous with whether or not the student would be better off or if the academe or in your discipline would be better of, but may be very closely related to that.

Dear (name of student),

For complex reasons, I would not be the best person to write you this recommendation. However, I think you will be a good match for that program and wish you all the best in your future endeavors.