Final answer:
The Cabinet's role in decision-making has historically varied depending on the leader of the government and the type of political system in place, with differences evident between presidential and parliamentary regimes.
Step-by-step explanation:
Throughout history, the Cabinet's role in decision-making has depended largely on the individual at the head of the government, whether it be a president in a presidential regime or a prime minister in a parliamentary regime. In presidential systems, such as that of the United States, each president’s cabinet reflects their personal decisions regarding appointments and the functions of those cabinet members, as there is a significant variance from one presidency to the next in the degree to which cabinet members influence decision-making. By contrast, in parliamentary systems, there is generally more consistency in the expertise and input of cabinet ministers, who are typically also members of the parliament and play a substantial role in the legislative process.
For instance, George Washington's initial cabinet comprised only four members, but today, the U.S. cabinet consists of fifteen members. In many cases, presidents have tried to select a cabinet that not only has the required abilities and expertise but also reflects the country's demographics to some extent. Prime Ministers, on the other hand, tend to choose cabinet members from within their own party and parliamentary representatives, with more focus on political unity and the collective success of the party and prime minister.
Different cabinets have varied in their composition and influence throughout history, like Donald Trump’s cabinet being noted for its significant number of members from business backgrounds as opposed to prior governmental roles. Moreover, the concept of an 'inner' and 'outer' cabinet in the United States, with departments like Defense, Justice, State, and the Treasury usually carrying more influence, has evolved over time. In parliamentary systems, the prime minister's relationship with their cabinet can greatly influence how much sway the cabinet holds in the decision-making process.