With the Confederate attack on Fort Sumter in April 1861, civil war became a reality for the United States. Each side in the conflict was forced to assess its strengths and weaknesses in search of the best strategy for victory.

The material resources for making war greatly favored the Union. Most of the nation’s heavy industry, including almost all of its firearms production, was in the North. The Union claimed great advantages in railroad infrastructure and its vastly superior navy dominated the seas. Perhaps most importantly, the Union’s much greater population provided a larger pool of potential soldiers for building armies and replacing casualties.

President Abraham Lincoln’s task was to find generals who could use these great advantages to prevail over the Confederacy. Unfortunately, his search for competent generals continued for most of the war.

Many of the army’s better officers, including Robert E. Lee, joined the Confederacy. Those who remained loyal to the Union included aging veterans of the Mexican War, such as Winfield Scott, and younger men with little experience.

Few officers were capable of leading the disorganized Union army in the field. This fact was demonstrated at the Battle of Bull Run, when the Confederates routed the Union forces 30 miles south of Washington. After that fiasco, Lincoln began the search for a worthy commander. His search carried him to former Mexican War officers who were no longer enlisted, such as George McClellan.

Upon his return to the military, the 34-year-old McClellan quickly rose through the ranks to become second in command only to Winfield Scott. McClellan took command of the Army of the Potomac with high expectations, but he consistently refused to move boldly against Lee and the Confederate Army.

McClellan attempted to capture the Confederate capital at Richmond but failed partly because he was timid to act and quick to retreat. He believed he was saving men’s lives. Lincoln argued that he was costing lives by prolonging the war. McClellan finally exhausted Lincoln’s patience at Antietam, Md., in September 1862 when he failed to follow and crush Lee’s defeated army. Lincoln removed him from command.

What followed was a revolving door at the head of the Army of the Potomac. Lincoln appointed Ambrose Burnside to command and ordered him to take decisive action. Burnside’s repeated assaults at Fredericksburg, Va., were turned back by Lee, causing Burnside to resign. Gen. Joseph Hooker was the next general to disappoint Lincoln, losing at Chancellorsville, Va., despite outnumbering Lee’s army two to one. Lincoln’s search for a capable general next led him to appoint George Meade in time for a battle at Gettysburg, Pa. Meade performed strongly at Gettysburg, defeating Lee in a bloody three-day battle that was probably the turning point of the war. The victory drove Lee from the North for the last time and set up the ultimate defeat of the Confederacy.

Like his predecessors, however, Meade failed to act decisively enough for Lincoln. Lee and his retreating army became trapped against the flooded banks of the Potomac River and Lincoln urged Meade to follow and destroy them. Instead, Lee’s army escaped across the river 10 days later.

As news of the Gettysburg victory spread through the ecstatic North, another Union victory made headlines. The town of Vicksburg, Miss., fell, giving the Union total control of the Mississippi River. The Union Army had always had greater success in the West, and here was an opportunity to promote the general responsible.

Ulysses S. Grant turned out to be exactly what Lincoln wanted: a bold commander who used manpower to his advantage. Grant led repeated assaults against Lee and the Army of Northern Virginia, each time emerging bloodied but intact. Rather than retreat as previous generals had, Grant continued to advance. He replaced his casualties while Lee didn’t have the manpower to overcome his own losses.

By waging war directly against Lee’s army, Grant drove the Confederacy to desperation. Plagued by shortages and desertion, Lee was forced to surrender to Grant at Appomattox Court House, Va., ending the Civil War. In Grant, Lincoln finally found his trusted general.