tooth and nail
Furiously or fiercely; with all of one's strength and effort. I know my brother has fought tooth and nail to be re-elected, so his victory tonight is certainly well earned. The elite troops have been placed around the perimeter to defend the palace tooth and nail from rioters.
tooth and nail, fight/with
Fight vigorously, with all one’s resources. The analogy to biting and scratching was drawn by the sixteenth century and has been used ever since for fierce contention or, by extension, effort. Dickens used it in David Copperfield (1850): “I go at it tooth and nail.”