The first whistleblower protection law was passed in 1778

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1773
Confidential letters exposed by Benjamin Franklin proved the governor of Massachusetts misled Parliament to promote a military buildup in the new world. The governor was dishonorably discharged and exiled.

1777
US naval officers Samuel Shaw and Richard Marven revealed the torture of British POWs by the commander-in-chief of the Continental Navy. The following year, the Continental Congress unanimously enacted the first whistleblower protection law.

1872
Julius Chambers, one of America’s first investigative journalists, admitted himself to New York’s Bloomingdale Insane Asylum and published an exposé proving patient abuse. 12 patients were subsequently released and laws were substantially re-written.

https://www.whistleblower.org/timeline-us-whistleblowers/