Thanks for continuing this discussion, because it is my belief that when it comes to “political generals,” it is easy to say, “He didn't do diddly” or “He was never any good” ...and miss the whole story. What follows is my interpretation of the above six listed generals (and I am more than happy to debate the performance of any of them, provided references are included.)
Beginning with Winfield Scott, the brevet Lieutenant General born in 1786, veteran of the War of 1812 and Commander of the Victorious Army which won the War with Mexico. Made Commander of the Army in 1841, General Scott continued in that role through the Buchanan Administration (and likely made decisions that resulted in Major Anderson being posted to Charleston Harbor in November 1860; sending Captain Don Carlos Buell to Charleston with verbal orders for Major Anderson in 1861; and sending orders to Lieutenant Adam Slemmer at Pensacola Harbor to “Hold the best fort.” There was no doubt that General Scott was past his prime, but “How does one remove an icon and War Hero?” Ask him: “Who should replace you?” Once Robert E. Lee disappeared as candidate for the role, General Scott advocated for Henry Halleck.
George B. McClellan. USMA Class of 1846 and Mexican War hero. Because of victories in minor skirmishes in Western Virginia (and elevation to militia Major General by the State of Ohio) George McClellan came to President Lincoln's notice at a time when he could use all the help he could get. Having survived ten days of terrible uncertainty at Washington D.C. following the Fall of Fort Sumter, and then suffering humiliation at Bull Run, President Lincoln was unwilling to wait for Henry Halleck to arrive from California; George McClellan arrived at Washington July 1861 and was installed as General of the Army (and Winfield Scott retired.) Upon request of President Lincoln, General McClellan provided Lincoln with a detailed “Plan of Offensive Operations” for the conduct of the war. (Meanwhile, Henry Halleck arrived from California and was installed at St. Louis in November, replacing Fremont and Hunter.)
John C. Fremont. A regular Army officer (but not a West Point graduate) Fremont was known as “the Pathfinder” to an adoring public (and as a Traitor by West Point graduates, due to political “interference” in California and the short-lived Bear Republic.) [Note: when California was admitted as a State in 1850, Henry Halleck wrote the State Constitution.] Fremont was married into a powerful Democrat family of Missouri politics; yet John Fremont became one of the original members of the Republican Party (and ran for President in 1856.) Fast forward to November 1860, after Lincoln's election as President, with war clouds gathering to the South. John Fremont met privately with Abraham Lincoln in Springfield Illinois; Fremont met with Lincoln during March 1861 and departed Washington D.C. in April, bound for Europe and a whirlwind series of visits to major arsenals and arms suppliers in Britain, France, Germany and Austria. After buying every serviceable rifle-musket available (and a number of artillery pieces) General Fremont returned to America late June, met with President Lincoln in Washington, and took command of the Department of the West, based at St. Louis in July 1861. The German and Hungarian communities of St. Louis rallied to Fremont; and his ties to the Benton Faction of the Democrat Party helped convince Unionist Missourians to forego the Rebel MVM (which became the State Guard), and join Fremont's Home Guard, instead. Making use of West Point graduate Nathaniel Lyon, offensive operations were conducted that drove Rebel forces away from St. Louis. St. Louis was fortified, protected by a ring of forts. And Fremont made use of Generals Hurlbut, Grant, Pope and Prentiss to commence driving Rebel forces out of Missouri. The loss of Lexington, the near loss of St. Joseph, and the death of Nathaniel Lyon highlighted shortcomings in Fremont's ability as military commander. These shortcomings were overblown by West Point graduates (who took delight in white-anting Fremont.) The “Pathfinder” signed his own Death Warrant when he issued an Emancipation Proclamation... and refused President Lincoln's demand to withdraw it. Fremont was removed from command at St. Louis. And Henry Halleck was installed as Commander, Department of Missouri on 9 NOV 1861.
Nathaniel Banks. A political animal with no military exposure, the Massachusetts native was able to become Governor, and was appointed Major General, strictly due to political connections. His record in the field speaks for itself.
John Dix. Born in 1798 this veteran of the War of 1812 had been Treasury Secretary at the end of the Buchanan Administration. Making himself available to President Lincoln, Major General Dix was installed at Baltimore (replacing General Nathaniel Banks.) In May 1862 General Dix was installed at Fortress Monroe (replacing the ageing General John E. Wool, who was two years older than General Scott). General Dix is most noted (and relevant to Battle of Shiloh captives) due to his collaboration with Confederate General D. H. Hill in Spring 1862, resulting in the Dix – Hill Cartel (formalizing a system of prisoner of war exchange).
Benjamin Butler. Politician who commanded the Massachusetts Militia, Brigadier General Butler answered the call and readied Massachusetts volunteers to be sent south after Fort Sumter erupted. After one regiment of Massachusetts men were impeded passing through Baltimore, and Baltimore subsequently closed to passage by any more Northern volunteers, General Butler commandeered a ferry, sailed his force of men to Annapolis, and against the demands of Governor Hicks of Maryland landed his force, defended the U.S. Naval Academy, and sent the Midshipmen away on USS Constitution (to establish the Naval Academy at Rhode Island for the duration of the war.) Butler rebuilt the rail line connecting Annapolis to Washington D.C. and guaranteed occupation of Annapolis (Capital of Maryland) by Union forces for the remainder of the war. “Following” orders from Lieutenant General Scott, in May 1861 Major General Butler occupied Baltimore... with no opposition. For violating his orders, Butler was recalled, and sent to command Fortress Monroe. (And Nathaniel Banks replaced Butler in command of Baltimore.) While attempting to expand the safe Union zone around Fort Monroe, General Butler's force got caught up in the Battle of Big Bethel. Although a Union defeat, the subsequent events at Bull Run overshadowed newspaper readers, and Big Bethel faded into insignificance.
Major General Butler commanded an expeditionary force in August 1861 that captured Forts Hatteras and Clark in North Carolina. Benjamin Butler then departed on recruiting duty in the Northeast... ostensibly to provide troops for another expedition; but in reality, these troops were sent to Ship Island off the coast of Mississippi. In April 1862 much of the combined Naval and Army force accumulated at Ship Island was sent up the Mississippi River in the operation to capture New Orleans. And Butler's 15000 troops were subsequently used to garrison New Orleans, Algiers, Fort Jackson and Fort St. Philip. (And when General Butler was replaced as commander of Occupied New Orleans in December 1862, it was Nathaniel Banks who replaced him.)
https://en.wikipedia.org/wiki/Winfield_Scott Winfield Scott.
https://www.historynet.com/mcclellans-war-winning-strategy.htm George B. McClellan
https://www.battlefields.org/learn/biographies/nathaniel-lyon Nathaniel Lyon.
https://en.wikipedia.org/wiki/Nathaniel_P._Banks Nathaniel Banks.
https://en.wikipedia.org/wiki/John_E._Wool John E. Wool.
http://www.mrlincolnswhitehouse.org/residents-visitors/the-generals-and-admirals/generals-admirals-john-dix-1798-1879/ John A. Dix.
https://en.wikipedia.org/wiki/Dix–Hill_Cartel Dix - Hill Cartel
https://www.militarymuseum.org/HistoryCW.html California Military History [Fremont, Halleck, Sherman, Ord, A.S. Johnston, Bear Republic]
https://www.militarymuseum.org/History Early CA.html California Military History [Sherman, Ord, Halleck]
https://www.battlefields.org/learn/biographies/benjamin-f-butler Unflattering bio of Benjamin Butler
https://www.nps.gov/people/benjaminfbutler.htm Benjamin Butler at Fortress Monroe and "Contraband Decision"
http://www.mrlincolnswhitehouse.org/residents-visitors/the-generals-and-admirals/generals-admirals-benjamin-butler-1818-1893/ Butler and Maryland