I try to be objective in my comments. I might have missed something in my assessment but my intent is not to be selective.
The DF-21D test I am aware of is the one which took place in the Gobi desert on a large stationary platform in 2013 (representing a stationary aircraft carrier).
There is another and it is similar in execution and similar target set.
I did not come across evidence of a test in which a
moving naval ship was involved, and struck successfully.
A ballistic missile have limited capacity for potential maneuvers, and it does not match a cruise missile in accuracy factor either. A cruise missile is the best choice to strike a moving target.
DF-21D is more of a propaganda weapon then being a practical weapon for its intended role. Americans have developed and tested similar stuff, so they know. They understand the game and potential stakes.
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Iran have sufficient knowhow to develop both
passive radar-guided and
active radar-guided ASBM such as Khalij Fars and Hormuz 2 respectively.
Test of Khalij Fars ASBM:-
It struck a stationary target in the sea.
Iran tested two Hormuz 2 ASBM in 2017. 1st ASBM missed its target. 2nd ASBM struck a floating barge. Confirmation here:
https://www.usnews.com/news/world/a...aunched-ballistic-missiles-us-officials-claim
You were saying?
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Iranian ASBM tests are more realistic than Chinese
but both have yet to test an ASBM on a truly realistic target which would be moving much faster and well-guarded on top.
Korean War (1950 - 1953)?
China dispatched a huge force to save North Korea from dissolution at the hands of US - certainly an achievement. However, US had much of its forces stationed in Europe and Japan at the time and was not expecting Chinese intervention in the Korean War.
US will take China seriously this time, and only
misinformed individuals would underestimate its military prowess in current times.
Regarding the highlighted part in your comments:
"The SM-6 was successfully tested by the U.S. Navy in December 2016 against a target representative of the DF-21D."
Source:
https://www.cbsnews.com/pictures/chinas-newest-weapons-of-war/3/
Two intercepts actually - independent assessment. However, these tests are classified to large extent.