The outbreak of the Mexican-American War in 1846 found Captain Beauregard supervising the construction of fortifications near Tampa, Florida. Eager for combat experience to enhance his changes of promotion, Beauregard received permission to go to Mexico in 1847 as part of Major General Winfield Scott's campaign against Mexico City. Reporting to Scott's command, Beauregard (along with captains Robert E. Lee and George B. McClellan) served as a staff officer to Scott, learning the intricacies of staff work, logistics, and personnel matters. With his knowledge of artillery and engineering, Beauregard played several important roles in the war. He supervised the use of siege artillery at Veracruz, demonstrated initiative against the Mexicans at the Battle of Contreras by revealing an opportunity to flank the enemy, and was one of the few staff officers to agree with Scott that a direct assault on the heights at the Battle of Chapultepec was the best option to capture Mexico City. However, whereas Scott singled out a number of officers for specific praise in his official reports, Beauregard received none, creating a paranoia for recognition that haunted him for the remainder of his military career.
Following the war, Beauregard returned to New Orleans as an engineering officer. He also dabbled in Democratic local politics (including an unsuccessful campaign for mayor of New Orleans). He also worked to ensure the election of Mexican-American War veteran Franklin Pierce as president in 1852. Pierce, however, selected another veteran, Jefferson Davis, as his secretary of war. Beauregard hoped that these fellow officers would assist him in gaining promotion. Beauregard also courted and married Catherine Deslonde, the sister-in-law of John Slidell, the powerful Democratic senator from Louisiana, a marriage that improved Beauregard's chances of advancing his military career.
Through Slidell's influence, Beauregard became the superintendent of West Point in January 1861. Only five days later, however, he resigned the post when his native Louisiana seceded from the Union to protest the election of the Republican Abraham Lincoln. A month later, Beauregard received a commission as brigadier general in the Confederate Army from Jefferson Davis, now Confederate president. Utilizing Beauregard's experience as an artilleryman, Davis sent him to Charleston, South Carolina, to assume command of local forces confronting the Union enclave at Fort Sumter. On April 12, 1861, Beauregard received orders from Davis to remove the Union garrison by force, and Beauregard's subsequent bombardment forced a Union evacuation two days later.
Arriving in the Confederate capital of Richmond to a hero's welcome in May 1861, Beauregard seemed destined for the accolades he believed to be long overdue. Instead, he found himself embroiled in personality clashes with his commander-in-chief. Jefferson Davis was perhaps somewhat envious of Beauregard's position as hero of the hour. He certainly did not appreciate Beauregard's advice on military matters. Beauregard believed he was in Richmond to supervise Confederate military efforts as senior commander, while Davis, the former secretary of war, believed himself quite competent to do that himself. Davis simply wanted Beauregard to supervise the defense of Richmond as commander of the local army, under command of General Joseph Johnston, who held the post of department commander. Beauregard favored a direct offensive action against Washington, D.C., with himself in command. It was Union forces, therefore, that took the offensive in July 1861, resulting in the First Battle of Bull Run. Beauregard, commanding the victorious Confederate Army, expected the accolades of the victor, but instead he felt snubbed when other heroes, such as Thomas J. Jackson, captured the public's attention. Continually irritating Davis over strategic policy and chafing under Johnston's command, in January 1862 Beauregard found himself exiled to Tennessee, where he found himself under similar circumstances.
Assigned to the Western theater, Beauregard served as a corps commander under General Albert Johnston, but similar irritations soon emerged. Beauregard continually offered unsolicited advice on operational matters and constantly planned, without Johnston's knowledge, for autonomous attacks by his corps into Tennessee and Missouri. These plans went on hold when Union forces under Brigadier General Ulysses S. Grant and Flag Officer Andrew Foote captured Fort Henry and Fort Donelson, forcing a Confederate retreat back to their railhead at Corinth, Mississippi. Beauregard joined his corps with Johnston's army in preparation for a counterstroke against the Union advance at Pittsburgh Landing, Tennessee. The resulting Battle of Shiloh (April 6–7, 1862) proved a professional disaster to Beauregard. Johnston's initial attack went well, routing the Union troops out of their unprepared camps. Johnston, however, was mortally wounded early in the battle, and it took some time to locate Beauregard to inform him that he was now in command. By that time, the daylight had faded, and Beauregard, anticipating the final destruction of Grant's army the next day, called off the attack for the night and sent off a triumphant telegram to Jefferson Davis and the Confederate War Department informing them of his great victory. Beauregard soon had to eat those words. The next day, Grant, reinforced by troops from Major General Don Carlos Buell's army, launched a counterattack that drove Beauregard's army from the field in disarray. Falling back to Corinth, Beauregard eventually evacuated this important position a month later. In retrospect, Beauregard did not deserve to take the brunt of the blame for the Confederate defeat. Although initially successful, Johnston's attack was already bogging down when he was killed. Had he been alive, it is doubtful that Johnston could have done any better than Beauregard on the second day of Shiloh or in the weeks after leading up to the evacuation of Corinth. Unfortunately for Beauregard, he was in command and had to take the blame. Davis removed Beauregard from command, replacing him with his own personal friend, Major General Braxton Bragg.
Beauregard found himself in the backwater of the war, once again commanding Confederate forces around Charleston. For the remainder of 1862 and throughout 1863, Beauregard ably defended the city, repulsing several serious Union attempts against Charleston from the sea. While successful in protecting the city, the failure of Union efforts resulted more from the daunting city defenses than from any tactical brilliance on Beauregard's part. In early 1864, Beauregard assumed command of the Department of North Carolina, embracing North Carolina and regions of Virginia south of the James River. Beauregard again ably defended the right flank of Richmond as Grant's Overland Campaign ground its way toward the Confederate capital in the summer of 1864. The primary task was containing Union Major General Benjamin Butler's assault at Bermuda Hundred. Once again gaining prominence, Beauregard soon ruined his credibility. When Confederate General Robert E. Lee's Army of Northern Virginia became locked in a siege in defense of Petersburg, Beauregard assumed (since Petersburg was within his department) that he would at least be the equal of Lee in coordinating the battle.
Instead, Davis dissolved his department and placed Beauregard and his men under Lee's command. Instead of accepting the demotion, Beauregard complained, and Davis shipped him off again. The last months of the war found Beauregard in a series of unredeemable situations. He served briefly under Major General John Hood in his disastrous campaign into Tennessee in late 1864, and tried unsuccessfully, as part of Joseph Johnston's army, to stop Major General William Sherman's campaign through the Carolinas in early 1865. Released from the army when Johnston surrendered in 1865, Beauregard returned to New Orleans.
In the postwar years, Beauregard prospered in a variety of business ventures, wrote his memoirs, and served in several public offices before his death in New Orleans on February 20, 1893. Perhaps the best summary of Beauregard's career is that he did specific important military tasks well, but could not translate that success on a larger stage. But, in his defense, he was also never given the opportunity to try.
Basso, Hamilton. Beauregard: The Great Creole. New York: Scribner’s, 1933; Williams, T. Harry. P.G.T. Beauregard: Napoleon in Gray. Baton Rouge: Louisiana State University Press, 1954.