Here:
[T]here will be situations in which the common good demands and requires that the executive go beyond the letter and even the spirit of the law. In these extreme or emergency situations — situations in which an existential threat poses a grave danger, with the survival of the political community itself at stake — the executive's extralegal decisions effectively become the community's higher law.
Probably the clearest example from American history is Abraham Lincoln's 1861 suspension of habeas corpus, defiance of the chief justice of the U.S. Supreme Court (who denounced Lincoln's actions as unconstitutional), and subsequent arrest (without charge) of pro-secessionist Maryland state legislators who appeared poised to condemn the suspension and vote to join the Confederacy.
Was Lincoln acting like a tyrant, as Maryland native John Wilkes Booth and many other critics of the time contended? You bet he was. And it's a good thing, too. Had Maryland seceded, Washington would have been surrounded by enemy armies and the South almost certainly would have won the Civil War quickly and decisively. Extralegal action was required to keep that from happening.
