Political group stop monarch being deposed (4)

I believe the answer is:

bloc

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'political group' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for bloc that I've seen before include "united nations" , "Political grouping of countries" , "International alliance" , "Group of allied nations" , "Political or economic confederation" .)

I've seen this clue in The Times.

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