The Obama administration announced last month via blog post that the president was unilaterally suspending ObamaCare's employer mandate—notwithstanding the clear command of the law. President Obama's comments about it on Aug. 9—claiming that "the normal thing [he] would prefer to do" is seek a "change to the law"—then added insult to constitutional injury. It also offers a sharp contrast with a different president who also suspended the law.

On April 27, 1861, President Lincoln unilaterally authorized his commanding general to suspend the writ of habeas corpus so that he could detain dangerous rebels in the early days of the Civil War. Lincoln's order was constitutionally questionable. The Constitution provides that "The privilege of the Writ of Habeas Corpus shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it."

A rebellion was in progress, so suspension was permissible. But the Constitution doesn't specify who can suspend the writ in such circumstances. Since the Suspension Clause appears in Article I of the Constitution, which is predominantly about the powers of Congress, there is a strong argument that only Congress can suspend the habeas writ.

Lincoln's order was legally dubious, but what he did next showed remarkable constitutional rectitude. On July 4, 1861, he delivered a solemn message to Congress, in which he did everything possible to square his action with the Constitution. In this message, he set forth the best possible constitutional arguments that he had unilateral power to suspend the writ. These arguments may have been wrong, but they were serious, and they were presented seriously, in good faith.

Lincoln also made a powerful argument about the necessity of his action. Even if he was wrong, and only Congress had the power to suspend the writ, surely the circumstances had to be considered: Congress was in recess and the South was in open rebellion. "The whole of the laws which were required to be faithfully executed, were being resisted, and failing of execution, in nearly one-third of the states," Lincoln said to Congress.