What it is
Constructive discharge is a legal finding, not a feeling: the working conditions must be so severe that a reasonable person would be forced to quit, and the employer usually knew. Harassment, protected-leave retaliation, and forced schedule changes are the common fact patterns.
What to do about it: Build the record before you quit: dates, requests, denials, and the written conditions. A resignation letter with no factual record is the hardest constructive discharge case to prove.
Plain-language description of US practice, not legal, tax, or financial advice. The paired guide carries the citations, dates, and thresholds; the state pages carry the local windows.