It is a dreadful misfortune for a man to grow to feel that his whole livelihood and whole happiness depend upon his staying in office.
 Theodore Roosevelt, Theodore Roosevelt; an Autobiography (1913). copy citation

Context

“Almost immediately after leaving Harvard in 1880 I began to take an interest in politics. I did not then believe, and I do not now believe, that any man should ever attempt to make politics his only career. It is a dreadful misfortune for a man to grow to feel that his whole livelihood and whole happiness depend upon his staying in office. Such a feeling prevents him from being of real service to the people while in office, and always puts him under the heaviest strain of pressure to barter his convictions for the sake of holding office.” source