Final answer:
The President of the United States is responsible for signing proposed bills into federal laws, which represents the final stage in the legislative process after a bill has passed both houses of Congress.
Step-by-step explanation:
The individual who signs proposed bills into federal laws is the President of the United States. After legislation is passed by both the House of Representatives and the Senate, it is sent to the president. If the president approves of the bill and its contents, they have the authority to sign it into law. This is the final step in the process of a bill becoming a law and it is a significant power vested in the executive branch of the federal government. However, if a president vetoes a bill, Congress may override the veto with a two-thirds majority vote in both the House and Senate.
The complexity of this process can be seen through various case studies involving environmental law and regulation, such as the EPA's handling of mercury emissions and the political and legal struggles surrounding the construction of oil pipelines. These examples illustrate the intricate balance between legislation, regulation, and the various stakeholders involved, including government agencies like the EPA, legislators, existing and new firms, and the public.