Henry Jackson Comics
The Presidency of William Henry Harrison (elected in 1840 to oust Martin Van Buren and the Jacksonian "dynasty"), in all honesty, did not very much effect the history of the United States.
The truth of the matter is that this man, no matter how skillful of a politician, or how honest and persuasive he may have been, simply did not have time to affect any real change in his meager 31 days in office.
Most accounts point to the beginning of the end for the new President at the event of his inauguration itself, when this thick-skinned former war-hero stood outside in cold, wet weather without an overcoat to deliver the longest inaugural address in American history - 8,444 words and about two hours long. The ensuing pneumonia surely contributed to his rapid decline.