Prior to dawn on 18 July the 4th Raider Battalion and fresh supplies arrived at Enogai. Most of the Rice Anchorage garrison had also moved up to join the main force. This gave Liversedge four battalions, but all of them were significantly understrength due to losses already suffered in the New Georgia campaign. The 4th Raider Battalion was short more than 200 men. The 1st Raiders reorganized into two full companies (B and D), with A and C becoming skeleton units. A detachment of the 3d Battalion, 145th Infantry, remained at Rice Anchorage. More important, the enemy at Bairoko was now aware of the threat to its position.
Liversedge issued his order for the attack. It would commence the morning of 20 July with two companies of the 1st Raider Battalion and all of the 4th advancing from Enogai while the 3d Battalion, 148th Infantry, moved out along the Triri-Bairoko Trail. The American forces would converge on the Japanese from two directions. Liversedge requested an air-strike on Bairoko timed to coincide with the attack, but it never materialized.
The movement toward Bairoko kicked off at 0800 and the 1st Raider Battalion made contact with enemy outposts two hours later. Companies B and D deployed into line and pushed through a series of Japanese listening posts. By noon Griffith’s men had reached the main defenses, which consisted of four fortified lines on parallel coral ridges just a few hundred yards from the harbor. The bunkers were mutually supporting and well protected by coconut logs and coral. Each held a machine gun or automatic weapon. Here the 1st Battalion’s attack ground to a halt. Liversedge, accompanying the northern prong of his offensive, committed the 4th Battalion in an attempt to turn the enemy flank, but it met the same heavy resistance. The raider companies slowly worked their way forward, and by late afternoon they had seized the first two enemy lines. However, throughout this advance enemy 90mm mortar fire swept the Marine units and inflicted numerous casualties.
The 4th battalion kept feeding companies into the line trying to find the flank of the Japanese position. But they continued to run into well dug in Japanese positions. Finally, late in the afternoon the 4th Raiders found what appeared to be an opening in the Japanese lines. It was a clearing and they hoped by driving through this they could begin to flank the Japanese positions. Company Q made an ill-fated attack which was stopped cold in mere minutes by severe and accurate Japanese mortar and machine gun fire. At this point the Raider attack stalled.
Meanwhile the southern prong of the attack was faring even less well. The Army battalion made its first contact with the enemy just 1,000 yards from Bairoko, but the Japanese held a vital piece of high ground that blocked the trail. With the lagoon on one side and a deep swamp on the other, there was no room for the soldiers to maneuver so the commander of the Army battalion pulled back his lead units and used his two 81mm mortars to soften the defenses.
When news of the halt in the southern attack made it to Liversedge at 1600, he asked the commanders of the raider battalions for their input. Griffith and Currin checked their lines. They were running out of water and ammunition, casualties had been heavy, and there was no friendly fire support. Neither battalion had any fresh reserves to commit to the fight. Moreover, a large number of men would be needed to hand-carry the many wounded to the rear. The 4th Raiders alone had 90 litter cases. From their current positions on high ground the Marine commanders could see the harbor just a few hundred yards away, but continued attacks against a well entrenched enemy with fire superiority seemed futile. Liversedge issued orders for all battalions to pull back into defensive positions for the night in preparation for a withdrawal to Enogai and Triri the next day. He requested air strikes to cover the latter movement.
The move back across Dragons Peninsula on 21 July went smoothly. After failing to provide air support for the attack, higher echelons sent 250 sorties against Bairoko to cover the withdrawal. The Japanese did not pursue, but even so it was tough going on the ground. Water was in short supply and everyone had to take turns carrying litters. The column moved slowly and halted every few hundred yards. In the afternoon rubber boats picked up most of the wounded and ferried them to the rear. By that evening the entire force was back in its enclaves at Enogai and Triri. Total American casualties were 49 killed, 200 wounded, and two missing-the vast majority of them suffered by the raider battalions.
The failure to seize the objective and the severe American losses were plainly the result of poor logistics and a lack of firepower. A Joint Chiefs of Staff post-mortem on the operation noted that “lightly armed troops cannot be expected to attack fixed positions defended by heavy automatic weapons, mortars, and heavy artillery.” Another factor of significance, however, was the absence of surprise. The raiders had taken Enogai against similar odds because the enemy had not expected an attack from anywhere but the sea. Victory at Enogai provided ample warning to the garrison at Bairoko, and the Japanese there made themselves ready for an overland assault. The raiders might still have won with a suicidal effort, but Bairoko was not worth it.