Despite the impressive array, Washington was really lacking in its defensive capabilities. General John G. Barnard, Grant's engineering officer, noted that many of the troops were not actually fit for duty because they were new recruits, untried reserves, recovering from wounds, or worn-out veterans. Bernard estimated that instead of 31,000, the actual number of usable troops was around 9,600. The capital was more vulnerable to Confederate attack than it seemed since with around 10,000 troops, the Confederate army matched the effective Union troop strength.