Final answer:
The Vice President of the United States holds the responsibility of casting tie-breaking votes in the Senate when a tie occurs on a proposed bill or nomination.
Step-by-step explanation:
The individual who is responsible for casting tie-breaking votes in the Senate is the Vice President of the United States. In their role as the president of the Senate, they do not usually have the power to vote except in specific circumstances. If there is a tie on a proposed bill or nomination, the Vice President has the authority to cast a tie-breaking vote to resolve the impasse.
This responsibility is part of a system of checks and balances designed to prevent any one branch of government from becoming too powerful. The Senate has additional powers such as confirming presidential nominees for cabinet positions, ambassadors, and Supreme Court justices with the advice and consent of the Senate, and ratifying treaties. These are all significant because they require the president to work with Congress and consider their interests when making key decisions.