Habeas corpus can be suspended only under very specific and extraordinary circumstances. According to the U.S. Constitution (Article I, Section 9, Clause 2), the privilege of habeas corpus "shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it." This means suspension is permitted only in cases of rebellion or invasion when public safety demands it. Historically, habeas corpus has been suspended in the United States only a few times, including during the Civil War by President Abraham Lincoln, in some counties in South Carolina during Reconstruction, during an insurrection in the Philippines in 1905, and in Hawaii after the attack on Pearl Harbor. Additionally, only Congress has the authority to suspend habeas corpus, either through its own affirmative actions or through delegated authority to the Executive. The Executive branch does not have independent power to suspend the writ. In summary:

• Habeas corpus suspension is allowed only in cases of rebellion or invasion.
• It requires that public safety demands such suspension.
• Only Congress may suspend habeas corpus.
• It has been suspended very rarely in U.S. history during extreme circumstances such as the Civil War and wartime emergencies.

This constitutional safeguard ensures protection against unlawful imprisonment except in those rare and serious situations where public safety is at risk due to rebellion or invasion.