The Civil War was a war of attrition. The South had the advantage of fighting on its home turf, but the North had the advantage of greater manpower. The South's manpower was spread out over a large area, while the North's manpower was concentrated in one place. The North also had a better-developed transportation system and more factories to supply its troops with weapons and equipment.
The South's manpower was concentrated in one place, but it was also spread out over a large area. This meant that Confederate generals had to divide their armies up into smaller units to cover more territory. It also meant that they couldn't concentrate all their forces at one time to attack the North.
The North's transportation system was better developed than the South's because it had been around longer and because it was developed by a centralized government rather than by individual states. This gave the North an advantage in supplying its troops with food, clothing and ammunition. It also allowed for a more effective use of railroads for troop movements and for transporting supplies from factories to soldiers on the battlefields.
The North also had an advantage in manufacturing because it had more factories than the South did and because it could draw on resources from other parts of the country when necessary. The Union blockade of Southern ports kept Southern factories from getting raw materials from other countries, which limited their ability to produce goods for both civilian use and military use during the war.
The Union blockade also prevented Southern ports from exporting cotton, which hurt Southern farmers financially because they were unable to sell their crops abroad for cash or credit that they could use to buy manufactured goods from Northern factories. The blockade also prevented foreign countries from buying Confederate cotton, which hurt Southern farmers financially by reducing their marketability overseas as well as by limiting their ability to buy manufactured goods from Northern factories with money they earned selling cotton abroad [source: McPherson].In addition, Southern farmers were unable to get new farm equipment or fertilizer from Northern manufacturers because of the blockade [source: McPherson]. As a result, Southern farms suffered crop failures due to lack of fertilizer and machinery maintenance [source: McPherson].
These factors contributed to widespread poverty among Southerners during the war years [source: McPherson]. In contrast, Northerners were able to continue earning wages at jobs in Northern factories throughout the war years [source: McPherson].
As a result of these factors, Northerners were able to maintain an advantage in numbers throughout most of the Civil War (although not at first). By 1864, there were 2 million men in uniform fighting for the Union Army compared with 1 million men fighting for the Confederacy.
The Confederacy did have some advantages over its opponent -- namely its ability to wage guerrilla warfare against Union troops once they left Confederate territory and entered enemy territory (which happened frequently). But guerrilla warfare wasn't enough on its own to win back control over all of America -- especially since guerrillas couldn't fight effectively against large groups of soldiers or against cities protected by fortifications (which is what most major cities in America became during this time period).