In its classic gun-armed form, the cruiser was intended usually for long-endurance independent operation, having a direct ancestry in the sailing frigate. The navies subscribing to this concept of cruisers employed them usually in connection with trade: the British, for instance, used such ships in defence of trade and the Soviets, in the conventional cruiser's final expression, the 'Sverdlov' class ships, in its destruction.

By way of contrast, other major fleets were concerned little with trade and business of empire, using cruisers as a more integral part of the main body of the fleet. Such was the American concept.

Whatever concepts had been cherished, many were summarily rendered obsolete by experience in World War II, particularly the idea of the 'balanced fleet' and its composition, organization and use. For more than a decade, however, these profound lessons were hidden because major fleets 'made do' with a vast number of obsolescent, though quite new, war-built ships. There was no money for development and no potential maritime enemy to stimulate it.

This was the era of the Cold War, when the Stalin camp believed that the West was permanently on the brink of invasion, using its massive amphibious capability to outflank the Soviet armies in eastern Europe. These amphibious operations would need to be covered by the West's powerful carrier attack groups and, as these had also the means to deliver nuclear ordnance to Soviet soil, they were identified as the main target.

Most of a carriers defensive capacity, and all of her power to take the offensive, is vested in her aircraft. Once this shield is pierced, she is almost totally dependent upon her escort for protection. In the Pacific during World War II, the Japanese succeeded on occasion by employing sufficient aircraft to saturate the defences, which included an outer ring of destroyers and an inner ring of cruisers, and even battleships, whose upperworks were festooned with small-calibre automatic weapons.

By the Cold War period, however, technology had modified the threat to stand-off missiles capable, theoretically, of a range of 400 km (250 miles), launched from a combination of surface ships and aircraft. With a carriers combat air patrol lured away by a few such distant postures, a smartly-delivered conventional attack still had potency. The close-in escort was still required.

Between 1959 and 1966, two groups of specialized escorts were built, the 'double-ended' 'Leahy' class for close-in 'goalkeeper  roles and the single-ended 'Belknap' class which, having enhanced ASW capacity, provided 'outer-ring' ships. As neither type resembled the still numerous conventional cruisers and destroyers, they were labelled 'guided-missile frigates'. Significantly, one of each class (USS Bainbridge and USS Truxtun) was completed with nuclear propulsion, and these provided the basis for a pair of derivatives, 'stretched' by 10 m (33 ft).

The first of these, the USS Califomia (DLGN 36) was laid down at Newport News in January 1920, followed within the year by a sister ship, the USS South Carolina (DLGN 37). Interestingly, the two ships carried destroyer designations though classed as frigates. As both were completely unlike the European concepts of frigate design, they and comparable ships were reclassified as cruisers in 1975, a term more in keeping with their capabilities.

Similar to the earlier double-enders, the 'California' class ships were given a rather specialist 'close-in role, a somewhat narrow specification that allowed for no helicopters, despite an 11,000-tonne displacement. The two ships have a rather bland appearance with a featureless high-freeboard hull topped by a squat, two-block superstructure. Their inevitably under armed appearance gives little idea of their true potency.

Both forward and aft is a single-arm Mk 13 launcher for the Standard MR (Medium Range) surface-to-air missile, which replaced the Tartar. As this is essentially a close-range weapon, it must be assumed that volume of fire is the governing criterion, each launcher being sited above a rotating ring-type magazine with a 40-round capacity. With a speed of Mach 2.5 the missile has a flight time that even to maximum range cannot be much more than 40 seconds. Taken together with the need for simultaneous direction of the ship's two 127mm (5-in) guns, this necessitates a fire-control system that is agile both electronically and physically. The Mk 86 system, introduced on the 'California' class, has since been used extensively on other classes, including the 'Tarawa' class amphibious assault ship and the 'Spruance' class destroyer.

With a 'California' class ship tucked in on either beam, a carrier is both well protected and performance-enhanced through the cruisers' additional sensors and data-links. While highly efficient in such a 'goalkeeper' role, knocking down threats to the carrier, the ships lacked until recently any additional capacity to guarantee the elimination of threats to themselves, typically a 'leaker that penetrated the main defence ring. The Standard MR is viewed, it would seem, as suitable to double for a point-defence system, which is not fitted (even if it were, the standard Sea Sparrow is badly overdue for replacement). Two Vulcan Phalanx CIWS mountings are due to be fitted. Even these fast-response and autonomous weapons have shortcomings. Current thinking favors a 25-mm or 30-mm CIWS that has the range and stopping power to explode or disintegrate a hardened SSM at a safe range; even with super-dense penetrators, the Vulcan's 20mm projectiles are apparently on the puny side even if the extra rate of fire is taken into account. Current Vulcan mountings cannot elevate to an angle sufficiently high to combat the terminal diver, even though the ship's own Harpoon SSMs can use this attack technique.

Nuclear submarines pose one of the gravest threats to a carrier, and even an escort of the size of the Califomia carries an ASROC launcher. Though this is a stand-off weapon, effective out to about 9 km (5.62 miles), targeting information would usually need to be acquired from other platforms as the ship lacks her own helicopters and, at the speeds at which she would normally operate, her hull sonars would be degraded in performance.

Both  the California and her sister South Carolina have also been retired into the reserve fleet .California in 1998

and South Carolina in 1999.