In some cases, a plaintiff will argue as part of his Title VII discrimination action that his former employer didn't fire him. But rather he was constructively discharged. That's fancy speak for being forced to resign.
But here in Pennsylvania, New Jersey, and Delaware, a plaintiff can't just prevail in a Title VII action by sayings that he was forced to resign because of discriminatory conduct. That's too subjective. Instead, here's the rule:
To show that he was forced to resign because of discriminatory conduct, the plaintiff must prove that his working conditions became so intolerable that a reasonable person in his shoes would have felt compelled to resign.
This inquiry is objective and the burden on the plaintiff is very steep.