Napoleon was an opportunistic leader who's military genius was unmatched and his political prowess very solid, but his goal of overtaking Europe ended his power. Napoleon was a powerful military leader who was able to gain the respect and admiration of France through his military victories. He saw the opportunity to be the French leader and jumped at it, but his goal of a unified Europe hurt him. His ego also played a part in his fall from power in his ill-advised decision to have his brother rule Spain. Napoleon's military power was so great that he came close to ruling Europe in its entirety before meeting the end. His rule over France was very successful and he was able to run a country very effectively.
He was even able to rule over three or four countries at the same time very effectively. Ruling Europe by one's self is too large a task and Napoleon should be faulted for his decisions at that point. Napoleon reached power through rising during a wartime because of his military successes. During a time of war promotions are made frequently and Napoleon became a general at a young age. Napoleon was able to move his troops much faster than any other country was able to move their troops. Napoleon's troops were also much larger than any of the others.
These advantages led to Napoleon becoming one of the greatest military leaders ever. Napoleon's political ideas were efficient and worked well to rule a country; he even adapted his ideas to help France run more efficiently. The Napoleonic Code gave equality to all male citizens and he rehabilitated the Catholic Church for his people, despite his belief in religious freedom. He created a bureaucracy with sub prefects, prefects, and mayors that ran France. All of these ideas helped France run smoothly. Napoleon's problem was that overtaking all of Europe was too difficult a task for any man.
He was forced to divide rule over some of the states that he conquered and he was not intelligent in giving Spain to his brother. Spain revolted allowing a England to have a country to land on in Europe. This decision hurt Napoleon and ended with England uniting the remaining European countries against Napoleon in the battle of Waterloo. Napoleons ego and greed in expansion probably stemmed from his want for war as a militaristic person, but this became the end of his reign.
In the end, Napoleon was a great leader whose need for ruling all of Europe hurt him. Had he been content in ruling a large portion of Europe he would have been known as a great leader. His ideas and militaristic approach benefited his country, but in the end one man's greed destroyed the greatness of their country.