Final answer:
The earliest federal government departments were created to execute the enumerated powers of Congress such as managing finances, diplomatic relations, and national defense, which were essential for the functioning and survival of the young nation.
Step-by-step explanation:
The earliest federal government departments, including the Treasury, Foreign Affairs (later State), and War, were created to address fundamental roles that were recognized as necessary under the new system of government defined by the Constitution. These roles were tied to the enumerated powers of Congress, delineated in Article I, Section 8 of the Constitution, which included powers to tax, regulate commerce, coin money, declare war, and raise armies. These departments dealt with the essential needs of the country, such as managing finances, diplomacy, and defense, which had been shown to be lacking under the Articles of Confederation. The Articles provided a weak central government without the independent power to tax or a well-defined means to raise an army, which had proven to be problematic, as seen in events like Shays's Rebellion.
Renowned figures assumed executive roles under President George Washington, including Alexander Hamilton as secretary of the treasury, Thomas Jefferson as secretary of state, and Henry Knox as secretary of war. These appointments reflected the trust placed in experienced leaders to help the national government assert itself in critical areas for the young nation. The creation of these departments was not due to the scarcity of secretaries, but rather the necessity of managing the key functions of a sovereign state effectively.