U.S. Navy Cruisers v. Destroyers v. Frigates

Historically, cruisers were specialized to conduct anti-aircraft roles and destroyers were specialized to conduct anti-submarine roles, but both the Ticonderoga-class cruisers and the Arleigh Burke class destroyers are now multi-purpose surface combatants that conduct both anti-aircraft and anti-submarine roles, in addition to being used against surface warships, missiles, and targets on land. The distinction between the two classes of surface combatants has basically ended.

This historical role of frigates has varied over time and now refers to a smaller surface combatant that is still suitable for anti-warship and blue sea navy roles, in contrast to a cutter, which is generally used in U.S. service by the coast guard in roles other than engaging conventional naval forces.

The U.S. Navy is phasing out remaining 13 Ticonderoga-class guided missile cruisers (a class which entered service in 1983) by September 30, 2027. Fourteen cruisers of this class have already been decommissioned. 

This is pretty much uncontroversial, because the 9,600 ton Ticonderoga-class guided missile cruisers are basically an older versions of the U.S. Navy's 8,300 to 9,700 ton Arleigh Burke class guided missile destroyers (a class which entered service in 1991), which it has 73 of, with more ordered. The Ticonderoga-class cruisers provide no significant capabilities not found in currently serving U.S. Navy Arleigh Burke class destroyers. 

All of the Ticonderoga-class cruisers that are still in service have the Vertical Launch Missile system (122 cells in cruisers v. 96 in destroyers) as their primary weapon, 5" naval guns (2 in cruisers, 1 in destroyers), two torpedo tubes, two 25mm machine guns, the Aegis suite of sensors and weapons control systems, two defensive Phalanx Close In Weapons Systems (just one in later versions of the destroyer), and can carry two helicopters, all of which they share with the Arleigh Burke class destroyers. The Ticonderoga-class have addition 0.50 caliber machine guns and 8 Harpoon missiles. The destroyer has a laser dazzler and in some recent ones an offensive laser. They have similar speeds, although the cruiser has an almost 50% longer range at low cruising speeds. The cruiser has a crew of 330 and the destroyer has a crew of 323. The destroyer carries two small boats, mostly for boarding missions.

Only  three 15,656 ton Zumwalt-class guided missile destroyers entered service (starting in 2016) and only two are in active service (twenty-nine planned ships in the class were canceled). The class was built around a major railgun weapon, or in lieu of that a 155mm advanced gun system, neither of which was ever built due to technical obstacles. It has a a crew of 175, a similar speed to other naval surface combatants, a helicopter and three helicopter drones, and two 30 mm cannons, which is less offensive and active defensive power than an Arleigh Burke despite its greater size. As a result, its role is undetermined. Mostly it is being kept around as a potential test bed for substitutes for its main gun of an undetermined type.

The other major U.S. Naval Combatants are frigates. The U.S. Navy has two kinds of them, the Littoral Combat Ship (in two designs, the 3,500 ton Freedom-class monohull design first commissioned in 2008 with 8 in service and 3 under construction, and the 3,422 ton Independence-class trimaran design first commissioned in 2010 with 15 in service and 2 under construction) which is being phased out early with seven already retired and no more planned beyond those already under construction, for the most part because the Navy does not feel that it has met its needs and because there have been some serious design defects. The U.S. Navy has also ordered the 7,291 ton Constellation-class guided missile frigate which is on order and is based upon a French design and projected to enter U.S. Navy service in 2029.

All older classes of cruisers and destroyers and frigates have been retired from active service in the U.S. Navy. The U.S. had already completely phased out the Oliver Hazard Perry-class guided missile frigates from its surface combatant fleet in 2015.

Several new classes of cruisers and destroyers have been proposed, but none have entered production. For example, the CG(X) program to replace the Ticonderoga-class guided missile cruisers was abandoned in 2010 on the grounds that it was duplicative of the Arleigh Burke class destroyers:

The CG(X) program was announced on 1 November 2001. An initial requirement for 18 CG(X) was raised to 19 under the plan for a 313-ship Navy in 2005.

A reassessment in 2007 suggested splitting the CG(X) into two classes, fourteen Zumwalt-sized "escort cruisers" and five 23,000 ton ballistic missile defense ships. There was political pressure for some or all of these ships to be nuclear powered.

The fiscal year (FY)2009 budget called for procurement of the first CG(X) in 2011, and the second in 2013. On 1 February 2010, U.S. President Barack Obama unveiled his proposed budget for FY2011. This budget called for, among other things, canceling the entire CG(X) program.

The program was cancelled in the 2010 Quadrennial Defense Review. The CG(X)'s mission will instead be performed by DDG-51 Flight III destroyers, after the U.S. Navy concluded that the ships could rely on off-board and space-based sensors and so did not need a radar bigger than the DDG could carry.

The ongoing DDG(X) program is looking for a post-Zumwalt replacement for the Arleigh Burke class guided missile destroyer. It optimistically targets a 2032 date to have the first member of this class built. Concepts for the DDG(X) imagine a hull and size and level of automation similar to the Zumwalt, and similar offensive and defensive weapons suites and a powerful laser weapon to use as an active defense system. But no specific design has been developed. The ability to reload the Vertical Launch system at sea is another capability that is currently being discussed as urgent for new ships and as a retrofit for older ships with these missiles.

Littoral combat ships can be specialized with modules, some of which are just beginning to enter service, for light surface warfare, anti-submarine warfare, naval mine countermeasures, light amphibious warfare unit support, and anti-smuggling roles. But none of these missions has been very successful or received a warm reception from the Navy. Instead, the U.S. Navy has largely abandoned the idea of having specialized surface warships (apart from aircraft carriers, amphibious transports for Marine units, and hospital ships). The U.S. Navy has also largely abandoned the mission of having ships well equipped to provide fire support for Marines or other troops in coastal operations (a role that the Zumwalt class has been supposed to fill).

The U.S. Navy is not even actively developing a modern counterpart to the battleship, a large, heavy surface warship with as many naval guns that are as heavy as possible as it could manage, and heavy hull armor. Battleships haven't been used in warfare since 1991, when they provided naval support fire for troops in the Gulf War, and left U.S. Navy service in 2010. There are no battleships in service anywhere in the world, although Russia's one solitary Kirov class battle cruiser comes close (Russia also has two somewhat smaller cruisers  and one Kirov class ship in the dockyard being refurbished).

Indeed, only a small number of world navies have any ships above the frigate class.

For example, only a few ships are viewed as cruisers today except by the U.S., which is decommissioning them, and the Russian Navy, which has three in active service. The Italian Navy has an aircraft carrier that it calls a cruiser and while "the Type 055 of the Chinese Navy is classified as a cruiser by the U.S. Department of Defense, the Chinese consider it a guided-missile destroyer."