Bell was a major-general in the Regular United States Army, commanding the Department of the East, with headquarters at Governors Island, New York at the time of his death in 1919. He entered West Point in 1874, and graduated 38th in a class of 43 in 1878, with a commission as second lieutenant of 9th Cavalry Regiment, a black unit.
Bell was awarded a Medal of Honor for his actions of September 9, 1899 near Porac on Luzon Island in the Philippines. According to the official citation, "while in advance of his regiment [Bell] charged 7 insurgents with his pistol and compelled the surrender of the captain and 2 privates under a close fire from the remaining insurgents concealed in a bamboo thicket.
A few months after the Balangiga Massacre of September 1901, President Theodore Roosevelt ordered Bell's commander General Adna Chaffee to adopt, "in no unmistakable terms," "the most stern measures to pacify Samar."
On December 7, 1901, Bell wrote a letter beginning with this introduction:
"the United States Government, disregarding many provocations to do otherwise , has for three years exercised an extraordinary forbearance and patiently adhered to a magnanimous and benevolent policy toward the inhabitants of the territory occupied by this brigade"
Bell followed this disclaimer with a long list of Filipino breaches against the laws of civilized warfare. The Filipinos had broken General Order No. 100. The Filipinos had broken Article 63 by wearing civilian clothes with no special markings and returning home between battles and "divesting themselves of the character and appearance of soldiers...concealing their arms...posing as peaceful citizens...They have improvised and secreted in the vicinity of roads and trails rudely constructed infernal machines propelling poisoned arrows or darts." Even the destruction of telegraph wires and bridges violated, in Bell's opinion, some section of Lincoln's General Orders. The time had come to fight fire with fire Bell declared. America should "severely punish, in the same or lesser degree, the commission of acts denounced in the aforementioned articles." In other words, Bell went on record as planning to violate General Order No. 100 and the accepted tactics of civilized warfare.
Bell elaborated on these orders in a series of circulars, which specifically bestowed on his station commanders the right to retaliate.
One circular by Bell explained, when an American was "murdered", soldiers were instructed to "by lot select a P.O.W.--preferably one from the village in which the assassination took place--and execute him."
Another circular rationalized that "it is an inevitable consequence of war that the innocent must generally suffer with the guilty" and that "a short and severe war creates in the aggregate less loss and suffering than a benevolent war indefinitely prolonged."
Bell warned his commanders that young officers should not be restrained or discouraged without excellent reason. "It is not necessary to seek or wait for authority from headquarters to do anything or take any action which will contribute to the end in view."
Bell reasoned that since all natives were treacherous, it was impossible to recognize "the actively bad from only the passively so."
Chaffee received copies of Bell's directive and was aware of Bell's plan to launch a war of extermination.
Most notable of Bell's numerous engagements with the Filipinos was that near Porac in the island of Luzon, in which he was wounded while leading a charge. Despite his war crimes, the U.S. awarded Bell the Medal of Honor, for "gallantry in action".
When the United States military forces of the Western Pacific concentrated in the Philippines, he returned to Manila in 1911, as military commander, until war with Mexico seemed imminent. He was then ordered home to take command of the 4th Division. The 4th Division remained in Texas City as reserve, and although at several times, he seemed about to cross the Rio Grande, he was never a part of the Mexican expeditionary force.
After the Mexican situation quieted, Bell was relieved of the 4th Division, and placed in command of the Department of the West. He remained in command at San Francisco, where he had once been acting adjutant, until America entered World War I.
In the early spring of 1917, Bell was transferred to the Department of the East at Fort Jay, Governors Island in New York City, and as commander of that department, assuming responsibility for Officers' Training Camps created by his predecessor, Leonard Wood, at Plattsburgh, Madison Barracks, and Fort Niagara. Bell's aide, Captain George C. Marshall was most directly involved in the logistical support for these camps, battling a lethargic army supply supply system to properly equip the volunteer citizen soldiers. These camps, in August, 1917, graduated the large quota of new officers needed for the new National Army and, to a large extent, to officer the new divisions of the east and northeast.
In the same month, Bell was offered and promptly accepted the command of the National Army Division to be organized at Camp Upton. Bell's venerable figure, as he addressed the officers, and the men of the newly-formed 77th Division at Camp Upton, in September and the ensuing months of training, will be remembered among the first impressions of a life, strange and full of new conditions.
Bell commanded the Division when the first newly-appointed officers climbed the hill and reported to their first assignment, through that formative stage when barracks were thrown together at a miraculous speed, and being filled at the same rate. Then, in December, he sailed for France to make a tour of the front, and observe, first hand, actual fighting conditions. He did not return until the latter part of March, 1918.
On his return, Bell failed the physical examination required for active service overseas. When the doctors decreed that he would not take his division to France, Bell was again given command of the Department of the East, and returned to his old headquarters, Governors Island, which command he held until his death, January, 1919.