"At your request, I am submitting my resignation."
So wrote now-former Attorney General Jeff Sessions in his resignation letter to President Trump.
Yet, no one reasonably believes that Sessions resigned. "At your request, I am submitting my resignation" is a termination, period.
Clients ask me all the time, about an at-risk termination. "Jon, what if we just have him resign? He can't sue us for discrimination, then, right?"
Wrong. Of course they can. Compelling someone to resign in lieu of terminating them is no different than terminating them. They are leaving your employment through your choice, not theirs. So, no, you can't avoid a discrimination or other wrongful termination lawsuit merely by forcing an employee to resign instead of firing them.
That said, there are a couple of advantages to couching a separation as a resignation instead of termination.
First, it might make it easier for employee to find a new job. (Mr. Sessions, meet Fox News.) A prospective employer is more likely to hire someone who resigned than someone who was fired, and the employee is not lying on their resume if they list "resignation" as the reason for separation (a fact you'll support if the new employer calls).
Secondly, an employee who resigns might not be eligible for unemployment. Or at least you can reach an agreement with the employee that he or she won't file for unemployment.
So, there you have it. No, there is no functional difference between a termination and a compelled resignation, yet there are some strategic reasons why you, and the employee, still might want a signature on the resignation letter.