The start of the war led to the dissolution of the treaty system, but the dramatic need for new vessels precluded a new design, so the Clevelands used the same hull as their predecessors, but were significantly heavier.

[2] The ship's belt armor ranged in thickness from 3.5 to 5 in (89 to 127 mm), with the thicker section amidships where it protected the ammunition magazines and propulsion machinery spaces.

[2][3] After completing fitting-out work, the ship got underway for initial training on 14 September, which was carried out off Hampton Roads, Virginia, and included weapons familiarization practice and aircraft operations.

Columbia then sailed for the Norfolk Navy Yard for repairs and alterations and then embarked on her shakedown cruise in Chesapeake Bay, which lasted from 16 October to 8 November The next day, she got underway and joined Task Group (TG) 2.6, which also included the fast battleship Indiana and the destroyers De Haven, Champlin, and Saufley.

She was then assigned Task Force (TF) 64, which included the fast battleships Washington and Indiana, and the destroyers Balch, Cummings, Nicholas, Woodworth, and Dunlap.

[3] The task force sortied on 27 January, bound for the Solomons; two days later, the ships' air search radars picked up a group of unidentified aircraft approaching the formation.

[3] The ships of TF 68 sortied again on 19 February, heading back toward the Solomons; this time, they were to divert Japanese attention from an amphibious assault force that was to land on the Russell Islands, codenamed Operation Cleanslate.

On the night of 20/21 February, the ships passed through Ironbottom Sound, the site of several major naval battles during the Guadalcanal campaign, and anchored in Purvis Bay the following morning.

[3] On 27 June, the ships of Cruiser Division 12 were transferred to TG 36.2, and they sortied later that day for Purvis Bay to take part in Operation Toenails, the invasion of the New Georgia Islands in the central Solomons.

Columbia fired some 943 rounds from her main battery and 525 shells from her 5-inc guns at Faisi before the Americans broke off and returned southeast to cover the withdrawal of the minelayers.

The ships of her task group spent the next two and a half months operating out of Espiritu Santo, patrolling in the Solomons and conducting training exercises in the area, but saw no further combat during this period.

[3] On the evening of 1 November, TF 39 cruised in Empress Augusta Bay in Bougainville, when shortly before 01:00, the American ships picked up a Japanese surface force approaching.

Defects with her main battery elevation gear identified during post-overhaul trials necessitated further work, and she was not ready to return to operations in the Pacific until 29 June.

There she rejoined Cruiser Division 12, which was a component of TG 32.12; the ships sortied on the afternoon of 29 August to participate in a mock landing at Cape Esperance, though the group was missing the battleships Tennessee and California, which had been delayed.

Columbia opened fire at 06:00 and spent most of the day bombarding targets on Anguar; one of her seaplanes crashed on landing next to the ship, though the crew was rescued and the plane was quickly replaced.

She carried out a similar schedule of bombardment over the following two days, though on 14 September, she also helped to cover the activities of underwater demolition teams as they cleared paths for the landing force.

[3] Columbia spent the next four days refueling and rearming, but these operations were repeatedly interrupted by the need to take evasive maneuvers in response to heavy Japanese air attacks.

By 13 December, the fleet had arrived off the target island, and the Japanese responded with concerted air attacks, which Columbia helped to defend against, shooting down one Mitsubishi Ki-21 bomber.

[3] Over the following few days, Columbia provided gunfire support to the soldiers fighting inland from the beachhead and contributed her anti-aircraft battery to the defense of supply ships that were bringing reinforcements to the island.

On the morning of 3 January, Japanese reconnaissance aircraft spotted the American fleet, which instigated a series of increasingly severe kamikaze attacks over the following two days.

As the vessels were preparing to enter Lingayen Gulf itself later that afternoon, a Mitsubishi A6M Zero kamikaze dove on Columbia, but heavy anti-aircraft fire forced the plane to pull up at the last moment.

Columbia nevertheless remained on station for the rest of the day, providing gunfire to soften up the beach defenses and then close-range support the troops as they fought their way ashore.

[3] Columbia remained at Seeadler Harbor From 19 to 21 January, where temporary repairs were effected to permit the ship to make the voyage back to the United States.

The ship departed on 22 January, bound for Pearl Harbor, and while en route, she met up with Louisville and the destroyer Walke, both of which had also been badly damaged in the Lingayen Gulf operation.

The ship departed to return to the western Pacific that day, joining Task Unit 12.5.5 for the voyage to Ulithi, which was by then the fleet's forward operating base in the Caroline Islands.

TG 74.2 was then sent south on 2 July to patrol against any Japanese naval forces that might try to interfere with the landing, though none appeared, and the ships of Cruiser Division 12 were soon ordered north to Leyte.

They arrived in San Pedro Bay on 5 July, and Columbia's crew immediately set about refueling, carrying out maintenance on the ship, and conducting training while in harbor.

[3] On 7 July, Columbia and her sisters in the division were assigned to Task Force 95, which had been created to sweep across the East China Sea to search for Japanese merchant shipping in the area.

They returned to the operational area on 3 August, and over the following days, the ships encountered a few Japanese aircraft, though the escorting combat air patrol shot them down or drove them off without incident.

They found that the Japanese garrison was in poor condition, owing to shortages of food and medical supplies; that most of the facilities had been destroyed by bombing during the war; and that coastal artillery batteries had been disabled by the removal of their breechblocks.