In December 1861 the two Houses in the US Congress set up the "Joint Committee on the Conduct of the War". Demands for oversight of military operations undertaken by the Union (Northern) forces had risen during that year as they suffered defeats and other setbacks. The death of Senator Edward Baker (one of a number of members of Congress who left Washington to fight) at Ball's Bluff brought congressional concerns to a climax. The Committee was formed - and was dominated by radical Republicans. Bruce Tap in his excellent book "Over Lincoln's Shoulder" (Lawrence, Kansas: University Press of Kansas, 1998 - ISBN 0-7006-0871-0) commented "The committee was composed of military amateurs who attempted to influence military policy with simplistic, outmoded ideas on the art of warfare." and concluded that "the committee's activities did have a substantial negative impact on the northern war effort."
In my view the committee stands as an example of well meaning legislators losing sight of their role in oversight, who end up interfering in the work they should be standing back from and scrutinising. Rather than investigating they took it upon themselves to harry Generals they distrusted and tried to pressure Lincoln into taking ill thought out actions.
I'm a strong advocate of greater powers for committees, especially at Westminster but the Committee on the Conduct of the War serves as a warning that powers must be used wisely, or harm can be caused.