Roosevelt is famed for his many achievements, but the oen that I consider most important is his fight against the economic corruption and greedy businessmen of his country. Few presidents dared to oppose powerful capitalists who, in many ways held the country in the palms of their hands. Roosevelt was not afraid to oppose them. His endeavors in this area included busting hugely competitive businesses that were engaging in corruption to further their ends and earnest regulation of businesses. Roosevelt is also well-known for his leadership of the Progressive Movement and for his founding the conservation movement as well as for imbuing Americans with a love for sports and exercise in the American nation.

Roosevelt was a man of many talents: naturalist, hunter, explorer, author, and soldier he was famed for his political diplomacy and decisive actions.

The first American to win the Nobel Prize, Roosevelt coined the term 'Square Deal" which described his domestic agenda of ensuring that each citizen would be treated equal under his policies. Roosevelt's other actions included completion of the Panama Canal, negotiating an end to the Russo-Japanese War, and actively demonstrating American power. America expanded and flourished under his regime. As Roosevelt said in his speech to France, 1910:

It is not the critic who counts & #8230;The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again… and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat. (Roosevelt, 1910)

Roosevelt did not fail

6. John Adams

I rate him as one of the five most...

Adams was also a great lawyer, diplomat, statesman, and political theorist.
I see his accomplishments lying in the fact that he encouraged the United States to come into existence by encouraging her to fight for her independence and by later assisting Jefferson in drafting the Constitution.

Recognized more today for his achievement than in an earlier time, Adams' possibly greatest achievement lay in the fact that he held the country together during factitious times. He signed the controversial Alien and Seditions Act and built up America's army and navy making the nation strong were war with France to occur. Admired for his peace actions, Adams prevented war from occurring with France, even thoguh he knew that his doing so would harm his popularity, and diplomatically managed his opposition with Hamilton so that no rift occurred in the country. Adams was correct: making peace with France did harm his popularity, but I see it as one of his greatest achievements -- if not his greatest. The fledgling American nation would not have been able to withstand the attack. Adams himself noted that as his greatest achievement and wished that recorded on his tombstone.

Sources

Carpenter, J.J. Jefferson's Views on Education Implications for Today's Social Studies 95 (2004): 140-141.

Schwartz, B. George Washington and the Whig conception of heroic leadership American Sociological Review, 43, 1983

Neely, ME The Last Best Hope of Earth: Abraham Lincoln and the Promise of America, Cambridge, Mass.: Harvard University Press, 1993

Roosevelt, T. Citizenship in a republic Speech delivered at the Sorbonne, April 23, 1910

http://design.caltech.edu/erik/Misc/Citizenship_in_a_Republic.pdf