Let's discuss the reasons and the contemporary assessment of the move:
In selecting Virginia as their battle-ground, the rebels committed a crowning blunder. At Montgomery, its very remoteness would have secured to it a sort of immunity from punishment. It is nearly a thousand miles, by the only practicable route, from Richmond. It is one of the most arduous duties to conduct a war so far removed from the base of operations. Our Government could hardly touch Montgomery for a year or two, at best; but Virginia is not two days' sail from the great centres of population at the North, New-York and Philadelphia, and is penetrated by magnificent estuaries, all of which we command. We still traverse without molestation, the whole course of the Potomac, from its outlet to Washington. We could not have wished the rebellion to take a better place for the concentration of our strength, or more untenable for defense. Had it chosen the extreme Southern States, it would have had the most powerful of all auxiliaries -- distance from the North, and an insalubrious climate, Had it taken the Southern prolongation of the Alleghanies, it would have a position almost inaccessible to attack. But it has chosen to risk all where it is really the weakest, and the North the strongest.<"A Short War Probable", New York Times, May 31, 1861.> Edited 4/18/19 by poster. Originally incorrectly stated as "March 31, 1861".