What is the primary responsibility of the U.S. Senate?

The primary responsibility of the U.S. Senate is to approve treaties. This function is critical as it allows the Senate to play a key role in foreign relations and ensure that agreements with other countries have the necessary support and legitimacy. In order for a treaty to be ratified, it must receive a two-thirds majority vote from the Senate, highlighting the importance of this responsibility in maintaining the framework of U.S. diplomacy and international law.

While the Senate also writes bills and conducts trials (such as impeachment trials), these tasks are not its primary responsibilities. Writing bills is a joint effort between both houses of Congress— the Senate and the House of Representatives. Conducting trials, particularly impeachment trials, is a specific function that occurs when the House of Representatives has impeached a government official, making it more of a duty that arises under certain circumstances rather than a primary responsibility. The oversight of the House is generally part of the checks and balances between the two chambers but does not reflect the centerpiece of the Senate's role in government.

Therefore, the approval of treaties is a distinctive and vital duty of the Senate, emphasizing its unique legislative responsibilities and influence in shaping U.S. policy on the global stage.