Which act allowed for the impeachment of a President for high crimes and misdemeanors?

The correct answer is the Tenure of Office Act. This act, enacted in 1867, was primarily designed to restrict the President's ability to remove certain officeholders without the Senate's approval. Although the act itself is not directly about the impeachment process, it played a significant historical role in that it was one of the catalysts for the impeachment of President Andrew Johnson. Johnson challenged the act, which ultimately led to his impeachment by the House of Representatives for violating it.

It’s important to note that impeachment itself is outlined in the U.S. Constitution. The Constitution allows for the removal of a President for "high crimes and misdemeanors," establishing it as a constitutional procedure rather than being defined by a specific act. The Tenure of Office Act highlights the complexities and tensions between Congress and the Executive Branch during Reconstruction but does not directly establish the impeachment process itself.

The other choices, such as the War Powers Act, Federal Employees Political Activities Act, and Impeachment Act (which does not exist in a formal sense), are unrelated to the specific constitutional basis for the impeachment of a president. The War Powers Act regulates the use of military force, the Federal Employees Political Activities Act governs political activities of federal employees, and there is no unique "