Bleeding Kansas While some other prominent leaders of irregulars in the
Bleeding Kansas border conflict shared these traits, Jennison was distinguished by his blatant plunder for personal gain. Jennison cooperated with
James Montgomery in opposing pro-slavery settlers and irregulars believed to be in league with
Border Ruffians. In command of nine men, Jennison "tried" and hanged Russell Hinds near the state line at Mine Creek for the offense of helping to return a fugitive slave to his master in Missouri. Returning a slave was not only legal, but required at the time under the
Fugitive Slave Act. Hinds had rejected the standard $25 reward ($515 in 2005 dollars), but did accept $5 reimbursement for his expenses in transporting the slave, who had agreed to return to his master while awaiting legal emancipation. The acceptance of the reimbursement was enough to convince Jennison to hand down a death sentence.
Civil War Prior to the outbreak of the
American Civil War, Jennison became a
captain of the Mound City Guards on February 19, 1861. Although not with Senator
James H. Lane's Kansas brigade during the
Sacking of Osceola, Jennison was associated with it and would soon join the fray after receiving a commission as colonel from
Kansas Governor Charles L. Robinson on September 4. On October 28, 1861, Jennison completed the organization and mustering of his
7th Kansas Cavalry. The regiment would become known as "Jennison's Jayhawkers." It immediately took to the field patrolling the Kansas-Missouri border to prevent the secessionist under
Sterling Price from crossing. Jennisons was a resolute
abolitionist; his sentiments on the matter were the subject of an article in
Horace Greeley's
New York Daily Tribune. The article reported Jennison as refusing to allow non-abolitionist soldiers to serve under his command, and asserting that "the slaves of [southerners] can always find a protection in... [my] camp, and they will be defended to the last man and bullet." While the regiment was at
Leavenworth, Kansas, in April 1862, Jennison, angered over
James G. Blunt being named
brigadier general in his stead, resigned from the army and turned to banditry as a
Redleg. Following the
Lawrence Massacre Jennison was once again commissioned a colonel and called into service by
Kansas Governor Thomas Carney. Jennison raised a regiment that would become the
15th Kansas Cavalry on October 17, 1863. In a particularly egregious incident late in the war, Jennison shot and killed 66 year old civilian David Gregg "on the public highway north of
Parkville ,
Platte Co. Mo." on September 15, 1864. Colonel Jennison commanded a mixed brigade of Kansas militia and volunteers resisting
Price's Raid in October 1864. However, in December he was arrested as the result of plundering while returning through Missouri after the pursuit of Price. Jennison was court-martialled and convicted on June 23, 1865, whereupon he was dishonorably dismissed from the service.
Postwar Jennison was elected to the
Kansas Legislature from Leavenworth County in 1865, reelected in 1867, and elected to the
Kansas State Senate in 1872. ==Death==