What does Nor have We been wanting in attentions to our British brethren mean?

The phrase "Nor have we been wanting in attentions to our British brethren" suggests that the speaker believes they have made considerable efforts to show respect, consideration, or support to their British counterparts. It implies a sense of hospitality or goodwill that has been extended, possibly in the context of a strained relationship or conflict. The use of "brethren" indicates a sense of kinship or shared identity, emphasizing that these efforts were made with the hope of maintaining a positive connection.