Final answer:
The Kyoto Protocol is a treaty designed to reduce global greenhouse gas emissions, which the US did not ratify due to economic concerns.
Step-by-step explanation:
The Kyoto Protocol, signed in 1997 as part of the international response to global warming, is a treaty focused on reducing greenhouse gas emissions. Although shaped significantly by US representatives, the treaty was not ratified by the United States due to concerns over economic impacts, particular resistance being from the Bush administration. In the context of the US Constitution, the president negotiates treaties and the Senate must ratify them with a two-thirds majority vote. The Kyoto Protocol represented global efforts to legally commit nations to curb emissions and address climate change issues, a key step following the United Nations Framework Convention on Climate Change (UNFCCC). The enforcement and effectiveness of this agreement have been subjects of debate, especially with the subsequent emergence of the Paris Agreement, demonstrating the ongoing international struggle to agree on climate action.