Final answer:
The states act as a 'laboratory of democracy', a term coined by Louis Brandeis, to innovate in policy-making, with successful initiatives often spreading horizontally across states and potentially to the federal level.
Step-by-step explanation:
The states serve as a laboratory of democracy to develop and test public policies, which allows for innovation without posing risks to the entire nation. This concept was highlighted by Supreme Court Justice Louis Brandeis, who, noting the potential for states to experiment with policy innovations, likened them to laboratories where social and economic experiments could be conducted. Examples of such state-led initiatives include California's standards for fuel emissions and states that established early women's suffrage laws ahead of the Nineteenth Amendment. Through this system, successful policies can diffuse horizontally across states and potentially be adopted at the federal level, fostering a dynamic and adaptive approach to policy-making where states learn from one another.
Answer: 1. Laboratory of Democracy