Final answer:
The independence of the judicial branch is maintained through life tenure of federal judges, the power of judicial review, and separation of powers. Judges are also internally limited by the need to justify their decisions and are subject to public scrutiny, which helps retain their impartiality and adherence to the Constitution.
Step-by-step explanation:
To ensure the independence of the judicial branch, several mechanisms are in place. Firstly, according to Article III, federal judges are able to hold their offices during good behavior, which generally allows them to serve for life. This life tenure protects them from undue political pressure, allowing them to make decisions based on the law and not on the whims of the current government. Secondly, the power of judicial review enables the judiciary to act as a check on the other branches of government by ensuring that laws are in accordance with the Constitution.
Alexander Hamilton, in Federalist No. 78, emphasized the role of the judiciary as separate from the other branches, with the key function of interpretation. This independence is further strengthened as the judiciary has no control over the enforcement or the funding of their decisions, confining them to the realm of judgment only. Finally, federal judges are subject to internal limitations: they must justify their decisions to higher and lower courts, and these decisions are open to public scrutiny.
The judicial branch has two main purposes as outlined by Article III: to protect the Constitution and individual rights, and to help states retain sovereignty over their own laws. As part of the system of checks and balances, the executive and legislative branches also play a role in ensuring judicial independence by nominating judges who are likely to adhere to constitutional principles rather than political agendas.