The most common and most likely answer to this crossword clue is the 3 plus 4 plus 2 plus 7 plus 3 plus 3 letter word THE TAIL IS WAGGING THE DOG
I've seen this crossword clue in The Guardian
T
H
E
T
A
I
L
I
S
W
A
G
G
I
N
G
T
H
E
D
O
G
Buddy explains!
The straight part
We know that "Where leader seemingly subservient" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case where leader seemingly subservient = the tail is wagging the dog.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.