Answer:
He contrasts them with "Fleets and Armies." This helps Henry emphasize that 'Great Britain has previously taken the matter from 'the diplomatic phase to the military phase.'
Explanation:
Antithesis is described as the literary device in which two contrasting ideas are juxtaposed in parallel form. It helps the author to create a balanced effect and provide a better understanding to readers.
In sentence 20, the 'love and reconciliation' are contrasted with 'Fleets and Armies' to signify that Great Britain does not consider the former('love and reconciliation') to be a viable strategy. It helps Henry to highlight that Britain has already taken the matter to the military phase and there is no scope to 'diplomatic options to resolve the issue.'