from a piece by Taylor Martin

Anti-Ship Ballistic Missiles (ASBMs)
More formidable than convention anti-ship cruise missiles are anti-ship ballistic missiles, which follow a curved ballistic trajectory, close at high speeds, and are extremely difficult to intercept. “ASBMs are regarded as a means by which technologically limited developing countries can overcome by asymmetric means their qualitative inferiority in conventional combat platforms,” Erickson and Yang note, “because the gap between offense and defense is greatest here.”[41] The development of anti-ship ballistic missiles threatens to significantly increase China’s ability prevent US ships from operating within the confines of the First Island Chain,[42] massively increase the area-denial “no go” zone for US surface ships,[43] and is likely the greatest technological threat to face U.S. carriers since World War II.[44] ASBMs bypass the US Navy’s superior air and undersea fleet defenses,[45] and their maneuvering warheads allow them to hit moving surface targets as well as fixed facilities.[46]
China’s anti-ship ballistic missile, the DF-21D, is a specialized variant of an existing medium-range ballistic missile with a maneuvering reentry vehicle[47] and is believed capable of hitting targets beyond the First Island Chain.[48] Like the DF-21 theater ballistic missile it is based on, the DF-21D variant is road-mobile,[49] allowing it to avoid the risks of a fixed launch position the launch vehicle to quickly leave the area after firing, increasing the DF-21D system’s survivability[50] and complicating efforts to interdict launch vehicles before launch. Terminal guidance is provided by active and passive radar and optical sensors mounted on the missile,[51] and long-range targeting  by ship or land-based over-the-horizon radar and surveillance satellites, all systems China has heavily invested in fielding.[52] The DF-21D can mount a conventional explosive warhead, or a variety of flechette kinetic penetrators and microwave warheads designed to “mission-kill” a US carrier by disabling antenna surfaces and electronics.[53]
Anti-ship ballistic missiles are enormously difficult threat to defeat. ASBMs are significantly more difficult to terminally intercept than traditional anti-ship missiles; while a SS-N-22 “Sunburn” travels above Mach 2, the DF 21D’s impact speed is roughly Mach 12, dramatically shortening the time shipboard defense systems have to detect, intercept, and destroy the missile. “At such speeds, [Close In Weapons Systems] get around a second to engage a maneuvering target, correct its stream of projectiles onto the target, and make the kill,” notes James R. Holmes.[54] Like advanced sea-skimming missiles, the DF 21D is capable of maneuvering during its terminal dive, making interception even more difficult.[55] Even if CIWS manage to overcome these formidable technical challenges and intercept an ASBM, shrapnel from the destroyed warhead traveling at high speeds is still likely to heavily damage the target.[56] Anti-missile missile defense systems and CIWS are also constrained by the size of the magazines, leaving a ship that had exhausted its defensive ordnance helpless. Missile defense systems mounted in vertical launch system tubes cannot be rearmed at sea, meaning that even if a ship managed to survive discharging all of its defensive weaponry, it would have to retire from the theater for weeks to return to port and rearm—frequent anti-ship missile attacks could still mission-kill US surface combatants without defeating their defensive systems.[57]