The Gulf of Tonkin Resolution increased the power of the executive branch by expanding the president's right to executive privilege allowing the president to introduce bills to Congress allowing the president to use military force without a declaration of war by Congress authorizing the president to choose the Senate Majority Leader

The correct answer is: allowing the president to use military force without a declaration of war by Congress.<br /><br />The Gulf of Tonkin Resolution, passed by the U.S. Congress in 1964, granted the president broad authority to use military force in Vietnam without a formal declaration of war. This resolution was passed in response to two reported incidents involving U.S. ships in the Gulf of Tonkin, and it effectively gave the president the power to escalate U.S. military involvement in Vietnam without the need for congressional approval. This expansion of executive power was controversial and was later repealed in 1970.