When Abraham Lincoln was sworn in as the 16th President of the United States 1861, his respect and appreciation for the rule of law was widely known. As a practicing attorney and elected public servant, Lincoln’s experience reinforced his belief that the rule of law and its equal application was the foundation of limited government. Moreover, Lincoln was a student of the Constitution and an accomplished lawyer. More than any president before him Lincoln understood how the law and the Constitution both empowered and restrained the president.
Secession and the investment and eventual surrender of Fort Sumter on April 13, 1861 put Lincoln’s commitment to the rule of law to its most severe tests. Lincoln believed that secession was unconstitutional and secessionists were organizing an armed rebellion that threatened the existence of the Republic. As such, these events demanded an immediate response. That response, however, unquestionably went beyond the generally accepted constitutional powers of the presidency.
Out of respect for the limitations of his office, Lincoln was slow to exercise his presidential authority in the first five weeks of his administration. However, the outbreak of armed rebellion required that he take a tight grip on the reins of power provided to the government in times of “invasion or rebellion”.
When Fort Sumter fell, the country and especially the military was not prepared for war. The Army consisted of about 16,000 soldiers scattered across the Western frontier and the Navy was pathetically small with ships of the line stationed off the coast of Africa and in the Pacific. Lincoln took immediate action and issued a proclamation calling for the states to supply 75,000 militiamen and calling for a special
session of Congress to convene on July 4. When the states activated the militia, Lincoln instructed the Secretary of War to pay private citizens over $2 million in government funds to help equip and train the new volunteers. The arbitrary spending of public funds seemed to violate Article 1 of the Constitution which requires that federal expenditures be supported by appropriations passed by the House of Representatives and approved by the Senate.
The rebellion also forced Lincoln to assume emergency war powers not specifically granted to the chief executive by the Constitution. Before Congress convened in July Lincoln ordered the arrest and detention of people involved in “disloyal practices” and suspending their right to petition for a writ of habeas corpus. After his initial call up of the militia, he issued a call for volunteers for three years of service, thus enlarging the Armed Forces without congressional approval. Another extremely controversial decision the president made was to institute a naval blockade of the areas in rebellion. Secretary of the Navy Gideon Wells advised Lincoln that the blockade was a violation of international law and certainly would provoke questions in Europe. Lincoln explained these and other of his actions to Congress when it convened on July 4 by saying, “whether strictly legal or not, were ventured upon what had appeared to be a popular demand and a public necessity; trusting then as now that Congress would readily ratify them.” Ultimately, Congress approved Lincoln’s extra- constitutional acts, albeit after the fact.
Article II of the Constitution does not specifically grant these emergency powers to the president. In fact, the founders reserved the power to engage in war only to Congress, and mentioned the suspension of habeas corpus in Article I (the section which outlines Congress’s authority). However, the presidency was also seen as the branch of government which had the independence and agility to respond quickly to threats that Congress would be unable to address.
To support his emergency actions, Lincoln called on his oath of office where he pledged “to preserve, protect and defend the Constitution of the United States.” When defending his suspension of habeas corpus, he asked “are all the laws but one to go unexecuted, and the Government itself go to pieces, lest that one be violated?” He saw himself in the difficult position of having to stretch his own legal authority to defend the whole legal and constitutional order. And so he defended his extra-legal prerogatives by appealing to the rule of law itself.
Lincoln and the Rule of Law Pt. I can be found here.
 Abraham Lincoln, “Message to Congress in Special Session,” in Abraham Lincoln: His Speeches and Writings, ed. By Roy P. Basler (Cleveland: Da Capo Press, 2001), 600-601.