Answer:
The 1974 Supreme Court case that held that executive privilege may not be invoked to deny the courts access to evidence needed in a criminal proceeding was United States v. Nixon.
Explanation:
The Supreme Court ruling in United States v. Nixon of 1974 is a landmark decision on the limits of the powers of the President of the United States in relation to the other branches of government and to the domestic information system.
As part of the Watergate affair, President Nixon was asked by the Special Investigator and later by Congress to publish tapes recorded in the White House, which could have contributed to the investigation of the affair. Nixon, however, refused to release the tapes and instead offered copies of some of the recordings. The Judge of the District Court for Washington DC insisted on the release of the tapes, and the dispute eventually came before the Supreme Court of the United States.
The Supreme Court had to decide whether the legislature or the judiciary had the right to demand that the President of the United States, and thus the executive, publish it, or whether, as Nixon argued, this would violate the principle of separation of powers.
In its unanimous decision, the Supreme Court first made it clear that it had the competence to determine to what extent the United States Constitution restricts the powers of the President, and that the Constitution provides that laws may be enforced against the President. With regard to the executive power of the President, it stated that, in any case, it would not be given priority when it comes to the publication of evidence that is demonstrably relevant in criminal proceedings. So the tapes had to be released.
