This chapter describes and assesses the movement over time away from mandatory death sentences upon conviction of certain crimes towards the introduction of discretion by judges or juries. The author seeks to identify the core reasons for this change and why mandatory death sentencing has almost universally been rejected by courts around the world. The author explains how this court-led restriction has involved applying a dynamic approach to fundamental rights and constitutional interpretation, embracing international standards in an evolving context on how the law of sentencing should be administered. The author provides strong anecdotal and empirical evidence on the wider reasons why mandatory death sentencing receives no strong support in theory or practice, from either those maintaining or administering this punishment or the public at large, and the role this has played in abolishing the practice. The author concludes that it is the development of international norms that has played a significant global role in reducing the scope and application of the death penalty based on evolving standards of decency, which in turn may lead to abolition itself.