Contemporary criminal justice is premised on a rights-bearing defendant safe-guarded by due process from arbitrary state punishment. The paucity of academic commentary on the role of the criminal defendant suggests that there is a common assumption that the role is static. However, the rights-bearing defendant is a relatively new concept. Through a legal history analysis, this paper demonstrates that the defendant's role can mutate in response to pressures placed on the criminal trial. Broadly, there have been three conceptualisations of the defendant: the penitent Anglo-Norman defendant; the advocate defendant of the jury trial; and the rights-bearing adversarial defendant. Importantly, the shift from one conceptualisation to another has occurred gradually, often without commentary or conscious effort to instigate change. There are many contemporary pressures that could be impacting on the rights-bearing defendant. The concept of a mutable defendant provides a new theory through which to analyse these pressures. This paper considers the introduction of adverse inferences regarding the right to silence and disclosure, and the rise of ‘digilantism’. These new pressures, it is suggested, help to facilitate a rhetoric of deservingness that goes against the rights-bearing defendant and raises the risk its role could once again be mutating.