Final answer:
Federal civil service employees are legally prohibited from actively participating in political campaigns and using their federal authority to influence election outcomes due to the main provision of the Hatch Act of 1939.
Step-by-step explanation:
One of the restrictions placed upon federal civil service employees is that they are prohibited from engaging in certain political activities. This prohibition is a result of legislation like the Hatch Act of 1939 - also known as the Political Activities Act. The Hatch Act's main provision bars federal employees from actively participating in political campaigns and from using their bureaucratic authority to influence the outcomes of elections or nominations.
Federal civil service employees are obliged to adhere to this principle as a condition of their employment to maintain a federal workforce that is free from partisan political influence and to ensure that the functioning of government is not compromised by political allegiances. The civil service sector underwent reforms to reduce the impact of politics, emphasize qualifications and competence through exams, and create the United States Civil Service Commission to enforce the rule of law within the sector.
Violation of these rules can result in disciplinary actions, including removal from federal service. It's critical for civil servants to understand these boundaries and operate within the legal framework established to preserve the integrity of public service.