In the kipper fleet the Captain - front or back was also the mission commander although the Tac Nav was 'in charge' of the tatic.
On teh E3 on the other hand the AC/Captain/Pilot is responsible for the safe operation of the ac but the man who makes the beast work is the MC (US/NATO) or TD (UK).
If the pilot does not do what the TD calls then he may get shot down or have a misison failure on his hands. OTOH if the TD tries to 'hazard' the ac in pursuit of the mission the AC has the casting vote. Quite democratic really.