Oklahoma baseline
At-will employment is the starting rule, not the end of the analysis.
Oklahoma's uniform jury instruction describes indefinite employment as generally terminable by either side without breach liability, subject to statutory, contract, and narrow public-policy exceptions.
First determine whether the employment was actually at will. Review written contracts, offer terms, collective-bargaining agreements, public-employee rules, appointment documents, handbook disclaimers and promises, compensation plans, and any agreement limiting termination. Do not assume a handbook creates a contract or that an at-will clause resolves every statutory claim.
Then define the separation. Preserve the termination notice, resignation, schedule or duty changes, leave status, communications, access cutoff, final pay, and benefit notices. A constructive-discharge theory requires more than a worker feeling compelled to leave. Current law and facts control whether conditions and employer intent or responsibility meet the standard. Record who made the decision and when it became final.
A morally troubling or factually wrong reason is not necessarily illegal. The question is whether the discharge violated a specific statute, enforceable agreement, protected right, or clear Oklahoma public policy under a viable cause of action. Avoid telling a worker that ‘at will means anything goes’ or that any exception automatically applies.