WI: Lee at the Alamo

Sort of inspired by this thread.

What if the events as described in Lee at the Alamo actually occur (Twiggs doesn't take command; As Virginia hasn't seceded yet, Lee defends the Alamo; after a short while, the Texans dig up some artillery and Lee surrenders the Alamo, but by this point, a national hero...in the North. Suffice to say that the Confederacy is significantly less eager to offer him leadership of the Confederate Arms Forces. Lee, in turn, is assigned by Lincoln to the Mississippi theater, commanded by Grant OTL.

In what ways would Lee's command differ from Grant's, and how would this affect the campaign, and the war at large?
 
I expect he'd prove more aggressive than Grant was in OTL, meaning that he'd likely see the USA retake the Mississippi even faster than OTL.

More interesting is what happens to the war in the East - who heads the Union Army? And without Lee at the helm, does the Army of Northern Virginia hold out as long as it did?

One other thing to consider - Stonewall Jackson was with Lee at the Alamo in this story, giving the Union another top notch commander that OTL fought for the CSA.
 
That makes more sense as they were both 2nd Cavalry men.

Let's assume McClellan whips old Granny Lee's replacement in West Virginia. I think Little Mac still rises to the top of the AoP. Davis and Beauregard don't get on so Joe Johnson still gets the Virginia command. The two Johnsons versus Lee and McClellan. Interestingly Lee was A.S. Johnson's no.2 in the 2nd Cavalry. Thomas and Hardee were their majors. I wonder if Lee bumps Thomas up the command tree faster as a result?
 
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