Pulitzer Prize-winning Civil War historian James M. McPherson’s biography Tried by War: Abraham Lincoln as Commander-in-Chief
focuses on how Lincoln won the Civil War while arguing that the man forever redefined the role of the president in America.
The book largely eschews details about Lincoln's personal life or his rapport with colleagues in favor of a clear and concise summation of how the sixteenth president saved the country. In the broadest terms, Lincoln did this by clearly formulating the goals of the war, communicating these goals to diplomats, generals, and colleagues, and then working tirelessly to mobilize the public in favor of these aims. Of course, no matter how well formulated his plans were, Lincoln still had to execute those plans as effectively as possible. McPherson discusses how Lincoln willfully overcame the checks and balances set upon peacetime presidents in order to define fully how a president must act quickly and unilaterally during times of war.
In terms of declaring war, McPherson frames Lincoln's decision within the context of the Constitution. While the Confederacy would try to argue that the war was a question of states exerting their rights in the face of a tyrannical federal government, Lincoln—as a talented lawyer with a keen legal mind—was confident in his interpretation of the South's secession in regards to the Constitution. That interpretation amounted to this: The South was in open rebellion, its actions unequivocally treasonous against the United States of America. Further, to allow the South to secede would have been a dereliction of Lincoln's duty as a preserver of the Constitution.
In contrast to Lincoln's moral certainty of engaging in all-out war against the South, was his lack of experience as a military commander. Such a task would be difficult for any newcomer to military strategy, but the situation was made direr by the fact that Lincoln had to virtually build up the United States Military from scratch. As it stood at the time of General Beauregard's firing at Fort Sumter in 1861, the U.S. Military numbered a mere 16,000 men. Too many of these men were high-ranking officers long removed from the scrum of battle. Moreover, a third of them would defect to the South.
Filling the army with more bodies was not the only problem Lincoln faced. He quickly learned that the current commanders—in particular, General Winfield Scott—were ill-equipped to handle the task at hand. Not only did Lincoln believe these commanders lacked the ability to stop the South, he believed few of them even cared. Therefore, Lincoln sought out like-minded political allies to fill key commanding officer positions in the Union Army. As expected, some of these appointees excelled, others did not. Nevertheless, McPherson argues that, largely, the majority of these appointees took to military duty with talent and zeal. He particularly singles out John Logan of Illinois and Daniel Sickles of New York as talented officers. More importantly, Lincoln found that his political appointees, at worst, were no less talented as military commanders than most of the career West Point graduates who had filled the officer ranks. At least the men Lincoln appointed shared his passion for suppressing the Southern rebellion.
The problem of motivation among the career generals came down to their comparative old age, McPherson writes. Most of the distinguished generals at the time had made their careers driving Native Americans out of Georgia decades ago, or fighting in the Mexican-American War more than ten years earlier. Younger career officers, such as William S. Rosecrans, John Pope, Ambrose E. Burnside, Joseph Hooker, and Henry W. Halleck, were, perhaps, sufficiently enthusiastic about defeating the Confederacy, but Lincoln felt that they were far too risk-averse to make the kind of bold decisions needed to win the war. Lincoln learned he would have to make these decisions himself, and for much of the war was forced into the role of de facto commanding general of the Union Army.
McPherson frames Lincoln's broader military strategy in terms of three large goals: maintaining the safety and security of the nation's capital in Washington, D.C., keeping vulnerable states such as Missouri and Kentucky within the Union, and ensuring that morale among both troops and the larger citizenry did not suffer in the wake of inevitable military setbacks during the war. Keeping all of these balls in the air while effectively operating as the commanding officer of the military kept the status of the war precarious until Lincoln finally appointed a general capable of following and executing his strategy in Ulysses S. Grant.
Because the book focuses largely on how Lincoln defined the role of the wartime president, McPherson’s account of the rest of the war from this point on moves much more quickly. By humiliating the Confederacy's most-admired general, Robert E. Lee, and through Sherman's fierce march to the sea, and the burning of everything in between, the South was very demoralized. Lincoln won the war, preserving the United States for generations to come.