In chapter 68 of his autobiography, Ulysses S. Grant argues that although the north was more populated, industrialized, and richer, the Confederates had major advantages over the Union.
His major points:
He writes: "Under such circumstances it is hard to conceive how the North showed such a superiority of force in every battle fought. I know they did not...I deem it safe to say that there were no large engagements where the National numbers compensated for the advantage of position and intrenchment occupied by the enemy."
Do historians buy Grant's arguments that the battle was pretty equal, or that thing might have even been tipped in the advantage of the South, and that the Union had a big uphill battle?
Grant makes some interesting points, but they don't really jive with modern scholarship (or even some scholarship from 150 years ago). To point one, the South absolutely had to please its population and worry about its internal and external politics. The Confederacy relied on states to provide for the "good of the cause," which was frequently a thorn in their side. As an example, North Carolina had abundant supplies of uniforms, but refused to send them to other needy units, instead saving them for their own Tarheels. As the old saying goes, the Confederacy was killed by State's Rights. While not exactly that simple, trying to balance a national government while pushing the idea that state sovereignty was supreme became a no-win scenario. The Confederacy also had to contend politically with its actions in recruitment. There were a number of reasons they excluded from the draft men who held 20 or more slaves, but it certainly did not sit well with the poorer men who didn't have such an option.
Politically in the South, if you were on Jeff Davis's good side, mistakes could be made. (See everything involving Braxton Bragg). If you stepped too far out of the line you could also be in peril of losing position. When Patrick Cleburne first proposed arming slaves and giving them freedom in exchange for Confederate service in 1863, the idea was quashed pretty substantially, and many historians speculate this was the reason he failed to gain higher rank.
To conscription, while what Grant says is basically true, its also only half true. If I said I had ten men, and all ten are ready and willing to fight, and you have 200, but only 50 are able and willing, it doesn't really help to say "Well but I have ALL my men, and you don't." The North had enough to not need the level of conscription the South used. And even with Southern conscription, even if they'd extended both ends, they still were grossly outmanned. Total War conscription also means everything else gets neglected. It one of the big reasons in WWII, for example, we stopped allowing volunteering, as we needed at least a certain number in war industries to maintain production.
Although the South had internal lines (mostly), that really only counts if you actually can move men and supplies within it. The South had far fewer lines of railroad, and by February 1862 (i.e. pretty early in the war), they lost both the Tennessee and the Cumberland Rivers, two vital interior lines. Railroads and Mountains meant the Confederacy being split into the three theaters was largely unable to help the others, save in a few instances. What I mean is, they only held interior lines in a few cases that mattered and could be utilized, while the Union was able to systematically weaken those lines. And the South perhaps didn't have to defend a "rear" so much as they had to defend a front that was 360 degrees. Union troops in 1862 and 1863 were all at once attacking up and down the Mississippi River, the Tennessee River, New Orleans, Mobile, Charleston, Richmond, and Eastern Tennessee.
"I deem it safe to say that there were no large engagements where the National numbers compensated for the advantage of position and intrenchment occupied by the enemy."
Perhaps he forgot about the campaign to Atlanta. At virtually every point, Joe Johnston positioned his army on good ground, and entrenched themselves. Sherman's response was to simply find a flanking route behind Johnston. He could do this because he had the numbers to keep some men in front, and others to flank. Johnston had no option but to keep retreating.
We could also look at his own major victory at Shiloh. There is no question the Confederates ruled the day on April 6, having driven the Union several miles back, nearly to Pittsburgh Landing. They held the advantage the entire day, but reinforcements from Buell's Army made the difference the following day. The Union could be reinforced, and the Confederates could not.
The Wilderness Campaign in 1864 is another good example. Although several major battles were tactical Union losses, their ability to replace numbers meant they could continue to pursue Lee's Army further south rather than pull back and regroup.
Having said all that, it doesn't in any way mean the battle the Union undertook was easy. The South did have some advantage in interior lines and early leadership, but the Union, with all its resources, all its capital, and all its people, still took four years to end the war. To use Grant's own way of thinking, the Union didn't have to gather all the resources, conscript all the possible soldiers, or commit all soldiers to the front lines, as the South mostly did, and they still won. The things Grant mentions are less Confederate advantages than ways of prolonging the inevitable.