The United States had won the west; they controlled all but three miles the length of the Mississippi; Admiral Farragut had taken New Orleans, largest city in the Confederate States.
You can take all the territory you want, it does make for a nice, shiny trophy, but if you don't hold what you take it gets away; the trophy is manufactured of fools gold rather than the real thing. For to conquer you must conquer people, not territory. Napoleon would have been emperor of Russia if territory was the thing.
...Mr. Lincoln...came to see something which he never forgot. The Southern Confederacy lived by its armies. While they lasted it would last and if they died it would die...(Bruce Catton, Terrible Swift Sword "The Last Struggle," 303.)
...
In mid-June [1862] the Confederacy...had owned no more than three miles of the Mississippi; by mid-August it held several hundred miles...(Ibid "A Long and Strong Flood," 379.)
Here I begin to have doubts about faulting McClellan completely. Everything every historian has written about him is still true: too slow, too passive, not enough belief, and it is also true that if he had been faster, more aggressive and a true believer that more of the Confederacy's war machine would have been destroyed. Halleck (McClellan's successor) too.
Halleck understood everything except the need to be in a hurry. (Ibid, 371.)
In...June 1862, Vicksburg was just waiting for someone to come and capture it...two divisions from Halleck's army could have taken the place with ease...But Halleck was still digesting Corinth. (Ibid, 375)
But you can't tar Farragut with that too-slow, not-daring brush.
...without waiting for Halleck it told Farragut to go ahead and smash the Vicksburg batteries the way he had smashed Forts Jackson and St. Philip. ...
Admiral Farragut was game but skeptical. ...At Vicksburg the case was very different...It could never just be occupied; it would have to be fought for...
Farragut tried. ...as he had anticipated...he had indeed got the bulk of his fleet past Vicksburg but that nothing noteworthy had been accomplished. (Ibid, 376.)
Speed and daring and zeal would have degraded more of the Confederacy's armies but degrading is not conquering, degraded life is not death, and I have yet to read anything anywhere that speed and daring and zeal would have killed the Confederate armies by the summer of 1862. It was not possible, there was no magic bullet, no atomic bomb, in 1862. The United sword was about as terrible as 1862 allowed; it could have been wielded more swiftly but you cannot get close to proving that the war would have ended in 1862 if it was wielded faster.
Here also I find my first fault with Bruce Catton's history. He has not accounted for one of his own great lessons: War, animated as it is by living things, takes on a life of its own beyond full control of those living things which animated it:
In the year that began with the retreat from Bull Run and ended with the retreat from the Chickahominy, the war became too great for any man to manage. ...The war was going to run its course...(Ibid, "Unlimited War," 361.)
And men could not fully control its course.