Stalemate, Withdrawal, & Glory
News of Mexico’s entrance into the war took a bit to reach General Fremont& those on the Oregon front. When the new reached Fremont on July 9 his troops were just concluding the Siege of Fort Langley in which his army captured both the fort, most of its supplies & cannon, & 1900 Anglo-Canadian troops taking out the main British mainland opposition for hundreds of miles. With the British threat, for the moment anyways, under control Fremont, along with 2500 of his roughly 7500 troops, began moving southward back to San Francisco to prepare for the invasion of California. In his stead he appointed 40 year old Joseph Johnston to the brevet rank of Colonel & left him in command. As Fremont began his long trek south Johnston continued the campaign north up the Fraser River & captured Fort Thompson on July 14. The Battle of Fort Thompson however ended any immediate plans for a continued offensive as the battle caused 2400 American casualties forcing Johnston to remain there until reinforcements arrived which he thought were unlikely to arrive soon.
As the Oregon front reached a stalemate once more back in Ontario things were once more on the move. Following the capture of Fort Erie General Taylor had expanded the US’s control over Ontario meeting only light resistance except for in small battles at Hamilton & at Reservoir Hill southwest of London. These small battle & skirmishes however had severely depleted Taylor’s supplies & though more was being shipped overland, due to Lake Erie being a battleground between each sides warships & commerce raiders, it was slow & subject to attacks by irregulars. That Britain also had landed 10,000 regulars in Maine, which had been a hotbed for guerrillas & militia skirmishing throughout it, that had helped the militias gain control of nearly half the state before continuing on to Montreal & now threatened upstate New York only further made up Taylor’s mind to withdraw back into New York in mid July. This withdrawal wouldn’t set well with many Americans who, after having suffered nearly 2000 casualties, saw the campaign as a failure. With the offensive stalled in the west, failed in the east, & a disaster at sea support for the war & President Slater began dwindling.
While things weren’t going as planned in the north, in Texas the fighting was only getting bloodier. Since the Battle of Bexar Generals Scott & Arista had more or less held their positions with only small skirmishes occurring while each general attempted to gather reinforcements. As volunteers & some regulars reached Scotts position south of San Antonio his army had grown to almost 8000. However Arista had also succeeded in finding troops & on July 10 with his army nearing 15,000 Arista went on the offensive once more. Arista moved quickly assaulting the surprised Scotts position on the Medina River & after the hour long Battle of Medina forced Scott to withdraw. Scott withdrew back to San Antonio slowly constantly skirmishing with Arista & cutting down his troop numbers. However this went both ways & by the time Scott entered San Antonio his numbers had dwindled to around 5000 why Arista’s remained at nearly 10,000. At San Antonio however Scott refused to withdraw & instead had his forces dig on the 15th in while riders set out towards Austin & Houston for help. As Scotts troops dug in Arista would be unable to drive him back & so as the Battle of San Antonio began it would see the first large use of trench & urban warfare in North America.
As the Battle of San Antonio raged Scotts riders luck prevailed when after arriving in Austin they found nearly 3000 Texans, many veterans of the Texas Revolution, had already been forming under Texas Senator & Texas Revolution hero Brigadier General Sam Houston. Upon hearing of the battle raging 80 miles south & on July 18 would lead the dubbed Texas Volunteer Brigade on a forced march to Scotts aid. As Houston headed south Scott was slowly but surely being pushed back as house by house the Mexicans uprooted the American defenders. Scotts headquarters was now in the iconic Alamo & the missions walls were now heavily garrisoned with cannon & troops. Despite the garrison Scott had begun to fear that the Alamo & San Antonio could fall as his troop numbers continued to drop. However on the morning of July 21 after almost three continuous days of marching Houston & the Texas Brigade arrived.
Though exhausted the Texans quickly made their way into the trenches & began fighting the Mexicans. The Mexican troops, equally exhausted as their American counterparts, upon seeing the arrival of new troops began to lose some steam in their attacks & by nightfall the entire battlefield had died down. It was during this lull that Scott & Houston decided to seize the opportunity & at 0400 the Americans & Texans attacked the Mexican lines. Though the Mexicans were caught sleeping the attack soon became a bloody hand to hand brawl that lasted over an hour, however by dawn Arista’s army was on the retreat &, after a week of intense fighting, the Americans had won the Battle of San Antonio.
The Battle of San Antonio was the bloodiest battle of the war yet as it had caused 1402 killed, 2166 wounded, & 400 captured or missing for the Americans & 2089 killed, 2488 wounded, & 1001 captured or missing for the Mexicans. Though the US-Texan Army was too battered & exhausted to pursue Arista’s army was in full retreat & Arista wasn’t able to stop them until they had reached Laredo. With much of the Mexican Army sent to capture San Antonio dead, wounded, or missing any thought of new offensives by Mexico quickly vanished. Following the battle the Texas front quieted down while both sides tried to regroup. Though the loss of life was staggering the Battle of San Antonio was quickly celebrated across the country as a glorious victory for the US & President Slater, seeing Mexico as the weak link in the Anglo-Mexican alliance decided to adopt a Mexico first policy & by the fall nearly 20,000 troops were being sent towards Texas.
Warfront End of Summer 1847