Rule 501.
Privilege in General

The common law—as interpreted by United States courts in the light of reason and experience—governs a claim of privilege unless any of the following provides otherwise:

• the United States Constitution;

• a federal statute; or

• rules prescribed by the Supreme Court.

But in a civil case, state law governs privilege regarding a claim or defense for which state law supplies the rule of decision.

(Pub. L. 93–595, § 1, Jan. 2, 1975, 88 Stat. 1933; amended Apr. 26, 2011, eff. Dec. 1, 2011.)