the most annihilating means of clouding the night
Sian Ede describing the poem by

Only a man harrowing clods
In a slow silent walk
With an old horse that stumbles and nods
Half asleep as they stalk.
Only thin smoke without flame
From the heaps of couch-grass;
Yet this will go onward the same
Though Dynasties pass.
Yonder a maid and her wight
Come whispering by:
War’s annals will cloud into night
Ere their story die.

says:
"He was wrong not just because by the middle of the century war’s annals were to include the most annihilating means of clouding the night, but because the simple agrarian life of the man harrowing clods was by the century’s end to change for ever, everywhere."

I can not understand the sentence "war’s annals were to include the most annihilating means of clouding the night". I know that "clouding into night" mean "disappearing" but what does "clouding the night" mean?*the poem "In Time of The Breaking of Nations" by Thomas Hardy

Question

the most annihilating means of clouding the night
Sian Ede describing the poem by

Only a man harrowing clods
In a slow silent walk
With an old horse that stumbles and nods
Half asleep as they stalk.
Only thin smoke without flame
From the heaps of couch-grass;
Yet this will go onward the same
Though Dynasties pass.
Yonder a maid and her wight
Come whispering by:
War’s annals will cloud into night
Ere their story die.

says:
"He was wrong not just because by the middle of the century war’s annals were to include the most annihilating means of clouding the night, but because the simple agrarian life of the man harrowing clods was by the century’s end to change for ever, everywhere."

I can not understand the sentence "war’s annals were to include the most annihilating means of clouding the night". I know that "clouding into night" mean "disappearing" but what does "clouding the night" mean?*the poem "In Time of The Breaking of Nations"  by  Thomas Hardy

Answer

I'm inclined to say there are two possible ways to read this: 1) that the author is purposely misinterpreting the phrase "cloud into night." I suggest this because, unless it is a typo on your part, the author has written that war's annals are "clouding the night." Which is to say, war is overshadowing the night. If that's the case, I assume he is referencing the devastating weapons of war that came about in the mid 20th century.

The second way to read it is that he does in fact intend to continue the metaphor, and believe's that the wars of the 20th century, as a collective, were so devastating, due to repeated massive attempts at genocide, the atom bomb, and other large scale acts of killing, that the wars themselves were erasing  history (as opposed to their histories "clouding into the night" on their own, as the poem suggests.)

All in all, I think this is sort of a poorly constructed sentence on it's own. It's possible that in the full context it makes more sense. Either way, I'm pretty sure he's referencing how intensely destructive 20th century wars were.