Magna Carta has long been understood as a source of inspiration for the U.S. Constitution, and especially its enshrinement of the writ of habeas corpus — the right of any prisoner to test his or her detention according to the law. In the “Suspension Clause” of the U.S. Constitution (Article I, Section 8), Congress is granted permission to suspend habeas corpus only “when in cases of Rebellion or Invasion the public Safety may require it.” This article surveys two failed attempts by the U.S. government to suspend the writ of habeas corpus. The first (which was actually the very first such attempt) was in 1807 and followed revelations of the so-called Burr Conspiracy. The second (incidentally the most recent in American history) occurred during the War on Terror and culminated with the Supreme Court’s decision of Boumediene vs Bush in 2008. A close examination of these two historical episodes reveals just how different were the constitutional processes of the early republic and contemporary times. Additionally, comparing the uses of Magna Carta during the two episodes demonstrates marked changes in American political culture. Historical consciousness, vital to early Americans’ understanding of their political system, has shifted to an elite level. Likewise, the protection of fundamental liberties has migrated from the popular branch of government (Congress) to the elite one (the Supreme Court). This article considers the implication of this shift in both constitutional processes and historical consciousness.