I disagree with /u/cazador5 on his analysis of Napoleon only because it's too broad and he doesn't focus on the Army of Italy under Napoleon.

With gaining command of the Army of Italy, Napoleon was expected to fail or at best, keep the Austrian army occupied while others push into Germany. With that said, the army of Italy could be compared to the Continental Army under Washington. However, the large difference is in that of leadership. Napoleon's Army of Italy and Washington's Continental Army were roughly the same size but the largest difference was the style of warfare.

Washington continued the focus on linear warfare that would continue up until the Revolutionary era. However, this would be due to both the people that trained his men (such as Baron von Struben) and the need for organization, however I can't speak much about Washington's army. Napoleon focused on fast, maneuver warfare to augment and help cover for the poor training and lower numbers of men that could fight. However, it was partly due to the interest of French morale (they would be better at moving and with bayonet charges rather than firing in a nice formal line), influence from Napoleon's reading (such as reading about Alexander, Julius Caesar, and other histories such as on Gustavus Aldophus and other famous captains of history), and the tactical ability to move around a more tactically inflexible enemy.

Further, the need to move fast and quick was because of poor logistics. This is before the high quality logistics that Napoleon depended on and his Chief of Staff Berthier certainly did a lot to simplify and make logistics easier. However, it would always be a problem because Italy was a secondary theatre to the French Director.

Training was kept to a minimum for the sake of speed, logistics, and need. Soldiers wouldn't need to be trained in anything but movement (formation movement and holding formation during combat).

The large difference between Washington and Napoleon is methodology. Washington was certainly an old style commander while Napoleon would be the proverbial cutting edge of military leadership.

Sorry, but your submission has been removed because we don't allow hypothetical questions. If possible, please feel free to rephrase the question so that it does not call for such speculation, and resubmit Otherwise, this sort of thing is better suited for /r/historicalwhatif.

First off I'm not an expert and there are probably plenty of people more qualified to post on this than I - it just so happened that I was doing some light reading on Napoleon and have already studied Washington's campaigns relatively closely.

LOGISTICS I think the first major difference was the sheer size of the forces each commanded. What many people forget is that the majority of major battles during the American Revolution were fought by relatively small contingents, especially when compared to contemporary armies on the European Continent. For an example I'll compare two of the more famous battles of the two commanders - Long Island for Washington and Austerlitz for Napoleon. At Long Island - one of the few large-scale, open engagements of the war - Washington had approximately 10,000 troops. The British had brought up a sizeable army of around 32,000 soldiers. Now it is important to note that neither side ever committed every soldier to any engagement, but those are good round numbers to work with. In contrast, at Austerlitz Napoleon had approximately 67,000 troops, and faced an Allied force of 85,400. You can see the stark contrast. As a result, engagements during Napoleon's wars often were exceptionally bloody, while in the Revolution large losses of life on the field of battle were rare. At Long Island, perhaps the most catastrophic defeat suffered by the Americans throughout the conflict (and part of the reason they were subsequently reluctant to engage the British openly), Washington's force lost around 1,000 killed or wounded, while another 1,000 were captured. In contrast Austerlitz, one of Napoleon's most famous victories, and one which hopelessly smashed the armies of the 3rd Coalition, resulted in over 7,000 killed or wounded on the French side alone, while the Allies sustained upwards of 25,000 casualties. You can see the difference.

While larger numbers obviously made battles more bloody, they also made logistics, organization and movement incredibly more complicated. Napoleonic generals encountered issues of scale that Washington simply never had to deal with. One should consider that Washington and his staffers were stretched extremely thin with the task of supplying, arming and clothing their troops throughout the war, with the example of Valley Forge being an extreme example. With an army of around 12,500 men, Washington's staff was severely stressed to find adequate food and shelter, resulting in the deaths of around 2,500 men to starvation, malnutrition and exposure. Napoleon invaded Russia with a force in excess of 650,000 all told, and of course many are aware that when supplies broke down, the majority of that force was killed, starved, froze or were captured. Napoleon was simply dealing with forces magnitudes larger than those commanded by Washington or his subordinates.

TRAINING I would say that the training utilized by the two generals was of comparable content, despite a 20 year separation. I'll get to this more in tactics, but training primarily consisted of drill and practice with arms, especially the rapid and sustained firing of muskets. In combination with drills that prioritized organization and mass movement, this training hoped to prepare troops for fighting on the battlefield.

What should be noted is that Napoleon and Washington commanded a vastly varying quality of soldier throughout either of their campaigns, and this would heavily affect the training of said armies. On Napoleon's campaigns in Italy before his assumption of the Consulship, for example, he commanded an outnumbered, demoralized and ill-equipped force that was use to defeat. This is not so different than the first vestiges of the Continental Army that Washington commanded following the Battle of Long Island, except of course in size and task. The goal of both generals was to make their forces a more viable fighting force. Napoleon chose to dive into the attack, and he was widely successful, fighting an offensive campaign despite his troops' condition. Washington took a similar route after he had been pushed across the Delaware in the late winter, and many know of his battles at Trenton and Princeton. But again, Washington's forces at Trenton were around 2,500, while Napoleon's 'tiny' Army of Italy numbered over 20,000 even at its lowest point.

TACTICS I've already discussed this a bit but the first thing to consider is that Napoleon fought in significantly more open engagements than Washington. Andrew Roberts has Napoleon fighting in at least 60 large-scale engagements throughout his career, while Washington fought at only one battle that could be considered first rate - Long Island, which he decisively lost. The wars fought by the two generals were incredibly different, so any comparison is at some level comparing apples to oranges unfortunately. Over all Washington's successes stemmed from rapid movements of forces through interior lines. His (or his subordinate's) quick occupation and fortification of Breed's hill led to the battle of Bunker Hill, which most consider to be an American success despite losing their position in the Charlestown peninsula. Similarly his rapid occupation of the Dorchester Heights, and their fortification, essentially led to the British evacuation of Boston. His famous siege of Yorktown was in some ways similar, as he was able to join his army to the American forces shadowing Cornwallis without alerting the strong British garrison in New York. Joined by a sizeable French contingent they outnumbered Cornwallis and affected his defeat.

Napoleon's tactics and strategy is the intense study of hundreds of historians. I can't give you a summary of any value but I can highlight some situations if you'd like to do further research. Napoleon is rightly known as a tactical genius, and there were numerous battles where he utilized superior movement, troop deployment and timing to break his enemies. Austerlitz is a classic example, and was perhaps one of the most decisive victories in history. Marengo was less the result of Napoleon's brilliance, but the steadiness of his forces held the Austrians at bay long enough for reinforcements to arrive and decisively turn the tide of the battle. At Ulm Napoleon successfully outmaneuvered and surrounded an Austrian army to such an extent that the entire force surrendered with minimal French casualties. At Jena-Auerstadt he used his flexible dispositions to build numerical superiority against the force opposing him. At the same time, his subordinate Davout resisted large-scale attacks from the main force of the opposing force, highlighting the discipline and morale of Napoleon's forces.

Of course Napoleon was not without his defeats. Disasters like the entire Russian Campaign, his battle of Leipzig and his final defeat at Waterloo had huge military and political consequences. But out of the 60 large-scale engagements that Napoleon fought in, only 7 can be considered defeats.

I hope this was somewhat helpful. There's a huge corpus of historical literature on the two people, so if anything I've said doesn't make sense or you're just looking for a good read, there is plenty of material to consult. I'll give you a couple sources, but again there's an incredible body of work out there.

For Washington and the American Revolution:

Ketchum, Richard M. The Winter Soldiers: The Battles for Trenton & Trinceton. Pb. ed. New York: Owl, 1973.

Ketchum, Richard M., and Richard M. Ketchum. Decisive Day; the Battle for Bunker Hill. Garden City, N.Y.: Doubleday, 1974. Lengel, Edward G. General George Washington: A Military Life. New York: Random House, 2005.

Wood, W. J. Battles of the Revolutionary War, 1775-1781. Chapel Hill, N.C.: Algonquin Books of Chapel Hill, 1990.

For Napoleon and the Napoleonic Wars in general:

Barnes, Gregory, and Todd Fisher. The Napoleonic Wars: The Rise and Fall of an Empire. Oxford: Osprey, 2004.

Bell, David Avrom. The First Total War: Napoleon's Europe and the Birth of Warfare as We Know It. Boston: Houghton Mifflin, 2007.

Rothenberg, Gunther E., and John Keegan. The Napoleonic Wars. London: Cassell, 2000.

Hope some of this helps!