Few presidents have interpreted their wartime powers as broadly as Abraham Lincoln, whose presidency—for all of its many successes—did have what some consider a "dark side." Most famously, Lincoln suspended the writ of habeas corpus in the first year of the Civil War, responding to riots and local militia actions in the border states by allowing the indefinite detention of "disloyal persons" without trial. Habeas corpus, which literally means "you have the body," is a constitutional mandate requiring the government to give prisoners access to the courts.
Lincoln ignored a Supreme Court justice's decision overturning his order, and over the next few years, the Great Emancipator, in one of the war's starkest ironies, allowed these new restrictions, which also imposed martial law in some volatile border areas and curbed freedom of speech and the press, to expand throughout the Northern states.
As the war drew to a close, though, some historians believe Lincoln may have begun to recognize the dangers of his own unprecedented expansion of presidential war powers. More than 13,000 civilians were arrested under martial law during the war throughout the Union. But it was in Missouri, in particular, nearly a thousand miles from the nation's capital and far beyond the federal government's day-to-day reach, that Lincoln was confronted with the most dramatic example of his internal security measures' unintended consequences.
In the months before he was assassinated, Lincoln found, to his surprise, that he was unable to convince Missouri's Republican leaders—who had grown accustomed to their newfound powers—to put an end to martial law in the state. The lesson he learned, historians say, may have been a simple one: "It is much easier," says Eric Foner, a professor of history at Columbia University, "to put these restrictions in place than it is to stop them."
When the war started, there was little doubt in Lincoln's mind that his suspension of civil liberties was both necessary and constitutional. His political opponents may have disagreed, but facing a full-fledged insurrection in the South and with the loyalty of Maryland, the state between Washington, D.C., and the rest of the Union, wavering, Lincoln had grounds to worry that the nation's capital was in real danger.
His worst fears were realized in the first month of the war, when a group of Massachusetts soldiers he had ordered south to protect the capital was attacked by an angry mob as the troops passed through Baltimore. The soldiers, panicking, fired into the crowd, killing 12 civilians. Four soldiers were killed, too. Ironically, they were the first casualties of the Civil War.
With Southern sympathizers beginning to cut telegraph wires and burn bridges behind Union lines in Maryland, Lincoln gave the order in April 1861 to suspend the writ of habeas corpus, allowing the Army to arrest and detain without trial those considered "disloyal." His order was limited, at first, to the rail lines between D.C. and Philadelphia, but it soon spread to the rest of the Union.
Legally, Lincoln felt he was on firm ground. The Constitution, after all, explicitly grants the government the power to suspend habeas corpus "in cases of rebellion or invasion," though it is not clear on whether this power resides with Congress or the president. In either case, before the war was over, the Union would face both rebellion and invasion, and in 1863, Congress passed a law, the Habeas Corpus Indemnity Act, in support of Lincoln.
Though he worried privately that these new powers might be misused, Lincoln publicly scoffed at the notion that his administration's suspension of civil liberties would have any long-term consequences. In a letter published before the 1864 election, Lincoln compared the wartime measures to the bitter medicine a patient takes when sick. He could not believe, he wrote, "that the American people will, by means of military arrests during the rebellion, lose the right of public discussion, the liberty of speech and the press, the law of evidence trial by jury, and Habeas corpus, throughout the indefinite peaceful future . . . any more than I am able to believe that a man could contract so strong an appetite for emetics [medicines] during temporary illness, as to persist in feeding upon them through the remainder of his healthy life."