Final answer:
A writ of habeas corpus is an important legal process in criminal justice that ensures an individual's right against unlawful detention and upholds the right to a fair trial.
Step-by-step explanation:
A writ of habeas corpus is a foundational element in the legal system, serving as a protection against unlawful detention. The term refers to a court order that compels the authorities to bring an individual before a court to ascertain whether he or she is being held lawfully.
Specifically, in situation c, when it involves a criminal matter, this writ ensures that a person's right to a fair legal process is upheld. If the state courts are unable to reach a decision, as hinted in d, or if a governor requests a federal court hearing as in b, a writ of habeas corpus might be sought to bring the matter before a higher authority.
In the United States, the right to habeas corpus is deemed so vital that it has historically been protected even during times of war or national threat, except under extreme circumstances.
This principle is coupled with constitutional guarantees such as the right to a speedy and public trial, an impartial jury, and the right to counsel. These rights are cornerstones of the Criminal Justice system where theory meets practice, and they ensure that the justice system operates transparently and fairly to protect individual liberties.
To summarize, the writ of habeas corpus is used to demand that a neutral judge decide whether someone has been lawfully detained, and it is a crucial aspect in the balance of national security and individual freedoms as demonstrated by historical cases such as Ex parte Milligan and Abrams v. United States.