Although Roosevelt was an able law student, he often found law to be irrational. He spent much of his time writing a book on the War of 1812.[29]
Determined to enter politics, Roosevelt began attending meetings at Morton Hall, the 59th Street headquarters of New York's 21st District Republican Association. Though Roosevelt's father had been a prominent member of the Republican Party, the younger Roosevelt made an unorthodox career choice for someone of his class, as most of Roosevelt's peers refrained from becoming too closely involved in politics. Roosevelt found allies in the local Republican Party and defeated an incumbent Republican state assemblyman tied to the political machine of Senator Roscoe Conkling closely. After his election victory, Roosevelt decided to drop out of law school, later saying, "I intended to be one of the governing class."[30]

Naval history and strategy
While at Harvard, Roosevelt began a systematic study of the role played by the United States Navy in the War of 1812.[31][32] Assisted by two uncles, he scrutinized original source materials and official U.S. Navy records, ultimately publishing The Naval War of 1812 in 1882. 