To begin, we need to examine two assumptions, as phrased by Joseph C. Goulden (from the University of Texas):
that he was a consistently brilliant military general who ranks as one of the foremost battlefield commanders in history, and that his most calamitous defeat, in his 1812 campaign in Russia, was chiefly a result of "General Winter," the fierce cold and snow that caught his Grande Armee deep inside Russia, hundreds of miles from home.
Perhaps Napoleon wasn't such an excellent commander, strategist, and tactician; and perhaps the Russian victory wasn't merely due to the weather, but rather to the skills of the Russian military.
Napoleon made basic military blunders in the campaign, chiefly by overextending his lines of supply and not providing the logistics necessary to support his army.
In a fight against lesser opponents, those blunders might not be fatal.
But the Russian high command contained intellectual generals who studied military history and knew how to apply the lessons learned to the battlefield. The commander in chief, Mikhail Kutnzov, shrewdly chose to avoid a set battle with Napoleon's superior force. Instead, he relied upon a tactic perfected centuries earlier by the Roman general Quintus Fabius Maximus, who used small unit harassing actions to wear down a larger enemy through attrition. The "Fabian strategy" worked to perfection (and the concept survives today as part of special operations doctrine).
In addition to an intelligent and skillful leadership, the Russian military had another advantage: horses. Dominic Lieven (from the London School of Economics) writes that:
immense herds dwelt on the steppe lands of southern Russia and Siberia,
In many years, the greatest hero of the Russian war effort in 1812-1814 was the horse [which] fulfilled the present day functions of the tank, the lorry, the aeroplane and motorized infantry.
Goulden concludes that
Napoleon could not replace the thousands of horses he lost during the campaign; hence Russian light cavalry relentlessly harassed his retreating columns.
A final Russian advantage was in the field of military intelligence:
Another area in which the Russians enjoyed an overwhelming advantage was espionage. Czarist agents in Paris and elsewhere elicited intelligence from many levels of Napoleon's government.
As the tide turned, and Napoleon's advance became a retreat, the war became one of attrition:
Once Napoleon was put on the run, he desperately fought major rear-guard battles that further depleted his ranks. The Russians, meanwhile, put together a massive logistics operation - 850 carts daily for food and forage, stretching back hundreds of miles. Czar Nicholas and his advisers made an astute political decision: They were not fighting "France" but Napoleon and his insatiable ambitions. His officers strictly enforced an edict to troops to "preserve the strictest discipline and treat the civilian population well." (One cannot resist comparing this conduct with the Red Army's brutality in the waning days of World War II.)
The Russian army of 1812/1814 understood what the Soviet-Russian army of 1945 did not: raping, torturing, and killing the civilian population, along with stealing their goods, burning their houses, and creating famines by annihilating their farms and food supplies are non-productive ways for occupying soldiers to behave. Even as the Russian army of 1814 crushed Napoleon's ego, it won the respect of the lands through which it fought. By contrast, the Soviet army of 1945 earned the contempt of the world by sadistically mistreating civilians.
The legendary proportions of Napoleon's humiliation could, and have, filled books; but
one statistic suffices:Napoleon's Grande Armee numbered 450,000 soldiers when the campaign began. Only 6,000 returned home.