There is a reference in James T. Dunlap's Civil War service record to his prior service in the Mexican War. I managed to find him listed in an index of Mexican War soldiers which indicated he had served in Company D of the Fourth Regiment of Illinois Infantry. The index listed his rank as both private and a sergeant. I then did an internet search to find out exactly what the 4th Illinois Infantry did during the Mexican War. I was fortunate to find a digital version of an old book with a very long title, "Record of the Services of Illinois Soldiers in the Black Hawk War 1831-32 and the Mexican War 1846-48". This book provided a complete list of men who served in all four regiments raised in Illinois during the Mexican War. It also provided information regarding the engagements in which the regiments participated. The book further indicated that a large portion of the army was recruited from the western states because men living on the frontier had a greater familiarity with firearms and it was much easier to transport them to Mexico down the Mississippi River.
As it turns out, James T. Dunlap had enlisted in the Fourth Regiment of Illinois Volunteer Infantry on June 9, 1846. He served in Company D of that regiment under Captain Achilles Morris. The Fourth Regiment was joined together with the Third Regiment of Illinois Volunteer Infantry to form a brigade. James T. Dunlap traveled with his regiment as far as Matamoros, Mexico. He fell ill there and was left behind on December 17, 1846 while the Fourth Illinois Volunteer Infantry marched down to Tampico, Mexico. On March 9, 1847 the regiment took part in the landing at Vera Cruz and played an important role in the subsequent battle of Cerro Gordo. Captain Roberts of Company A was the first man to place his foot on enemy soil in the landing at Vera Cruz. In a letter dated February 5, 1882, Second Lieutenant W. A. Tinney, of Company G of the Fourth Illinois Volunteers stated "We stormed their fort and put the enemy to flight, taking about six thousand prisoners, and we captured General Santa Anna's carriage, also his wooden leg, which I have in my possession."
It appears that James T Dunlap missed all of the action in the Mexican War due to illness. Approximately ten percent of the U. S. expeditionary force died from disease while only one percent died from battle. The difficulties of moving, feeding, and providing adequate sanitation for a large body of men in the 1840s led to serious problems with disease. His company of ninety-two men suffered a total of ten deaths. One man was killed by Mexicans on April 17, 1847 and one died by accident on April 16, 1847. The remaining eight deaths were from disease in October, November, and December, 1846. The surviving members of Company D were discharged at New Orleans, Louisiana on May 26, 1847.
Looking at all of the wars in which the United States has fought, the Mexican War was probably the least justifiable. It was mainly a grab for land. The United States wanted to buy land from Mexico which the Mexican government didn't want to sell. The main result of the Mexican War was to force the Mexican government to recognize the annexation of Texas as part of the United States and the forced sale of California, Arizona, and New Mexico to the United States. Abraham Lincoln, serving as a Representative from Illinois, opposed the Mexican War. The war was fairly popular in spite of its relatively weak justification. Lincoln's opposition to the war didn't help his political fortunes at the time and led to his decision not to seek re-election to congress. I discussed the Mexican War with a good friend who served a mission in Mexico and whose father had immigrated from Mexico. He acknowledged that there was poor justification for the Mexican War but expressed the wish that the United States had simply taken over the entire country of Mexico. He felt the Mexican people would have been much better off as it would have saved them from the long string of despotic and corrupt governments.
During the Civil War James T. Dunlap first joined the Union Army as a Captain in the 23rd Regiment of Missouri Volunteer Infantry. During the Civil War State governments often raised militia units which were then mustered into federal service. The governor appointed the commander of the regiment, then each individual company would elect their own officers. This James T. Dunlpa was elected to be a Captain in the 23rd Missouri Volunteer Infantry while he was later elected to be a First Lieutenant in the 44th Missouri Volunteer Infantry.
Captain Dunlap fought at the Battle of Shiloh, also known as the Battle of Pittsburgh Landing where he was wounded and captured. The 23rd Missouri arrived at Pittsburgh Landing by steamboat on morning of April 6, 1862, with the battle having started at daybreak. They were quickly marched to reinforce the Sixth Division of the Army of the Tennessee, under the command of Brigadier General B. M. Prentiss. The 23rd Missouri was initially assigned a position on the left flank of the Sixth Division. General Prentiss had been commanded to hold his position at all cost. The Sixth Division fought a defensive rear guard action as the rest of the Union forces retreated. They delayed the advance of the Confederate Forces which allowed Major General Ulysses Grant to establish a new line of defense. The area defended by the Sixth Division was named the "Hornet's Nest" because the fighting was so fierce. At some point the Confederate forces surrounded the Sixth Division and brought a significant amount of artillery to bear on their position. General Prentiss was then obliged to surrender his forces. More than 2,000 Union soldiers were captured, many of them wounded. Captain Dunlap then spent seven months in a confederate prison camp. The fact that he survived both a wound and seven month in a prisoner of war camp is pretty amazing.
Pittsburgh Landing on the Tennessee River was the strategic position the Union army was defending. The primary means of moving men quickly during the Civil War was by either rail or steamboat. The name Shiloh comes from a Hebrew word meaning "Place of Peace" and was the name of a church located somewhere on the battlefield. It is very ironic that one of the bloodiest battles of the Civil War should bear the name "Shiloh". The Confederate General, Albert Sidney Johnston sought to destroy Grant's Army of the Tennessee before Grant could receive reinforcement from General Buell's Army of the Ohio. The Confederate Army attempted a surprise attack on the morning of April 6, 1862. Although the confederates forced the Union Army back from their original positions, they failed to capture Pittsburgh Landing and destroy Grant's army. The reinforcements Buell's army began to arrive during the battle and Grant was able to mount a successful counterattack the following day. The Battle of Shiloh was the bloodiest battle in the history of the United States up to that time with over 23,000 deaths. Even though it was a Union victory, General Grant was severely criticized due to the heavy losses they suffered.
After James T. Dunlap's release from the Confederate prison, he served a term in the Missouri State Legislature. He then rejoined the Union Army on September 4, 1864, as a First Lieutenant in the 44th Regiment of Missouri Volunteer Infantry. He was wounded at the Battle of Franklin on November 30, 1864 and died of his wounds on December 11, 1864. In the Battle of Franklin the 44th Missouri Volunteer Infantry was assigned to the center of the Union army's defensive position. They successfully repulsed numerous Confederate attacks, but suffered severe casualties. Another ancestor, James Wesley Tunnell, Sr., also served in the 44th Missouri and was also wounded in the Battle of Franklin.
General Hood's Confederate forces were attempting to recapture Nashville, a significant manufacturing center for the South. The Confederate forces suffered such severe losses in the Battle of Franklin and the ensuing Battle of Nashville that they were forced to retreat south and were no longer able to mount any effective campaign. These were the last two major battles in the western theater of the Civil War.
James T Dunlap's military record includes a letter of recommendation that he be commissioned as a Colonel in the 44th Missouri Volunteer Infantry. The letter was written by an officer with whom he had served in the 23rd Missouri Volunteers, Lieutenant Colonel Isaac V Prato, and is dated August 1, 1864. The letter mentions that James T Dunlap had prior military experience from the Mexican War. The letter also mentions his having fought at the Battle of Shiloh and being a prisoner of war for seven months.