No man will ever be restrained from becoming President by any fear as to his personal safety.
 Theodore Roosevelt, State of the Union Address. copy citation

Context

“Moreover, his deed worked not the slightest dislocation in our governmental system, and the danger of a recurrence of such deeds, no matter how great it might grow, would work only in the direction of strengthening and giving harshness to the forces of order. No man will ever be restrained from becoming President by any fear as to his personal safety. If the risk to the President's life became great, it would mean that the office would more and more come to be filled by men of a spirit which would make them resolute and merciless in dealing with every friend of disorder.” source