As the Civil War began, each side had certain advantages and disadvantages.
The North had great advantages in manpower, material, and organization. It had more than twice the population of the South, and many more factories to produce war supplies. The U.S. government had been functioning well for many decades, and the national level had sufficient powers under the Constitution to wage war effectively.
The South had some advantages as well. Most Southern men were experienced in riding horses, hunting, and shooting. Its military leaders were experienced and effective, while the Northern armies struggled to find good leadership. Southerners were fighting to defend their own land, and thus had a strong incentive to fight well.
The political organization of the Confederacy, however, was a disadvantage to the South from a military point of view. The CSA constitution created a loose association of the individual states, and it was sometimes difficult to get all of them to work together smoothly.
The North used its advantages well as the war moved past the first year. It blockaded the South with a long line of ships to stop trade with Europe. It took control of the Mississippi River, thus dividing the South in two. It attacked deep into the heart of the South, winning control of large areas. With the victories at Gettysburg and Vicksburg in 1863, even many Southerners sensed that the days of the Confederacy were numbered.