Murderers and child predators

Is a cannabis possession charge really worthy of decades in prison, especially in states where it is now legal? Does it make sense that murderers and child predators often serve shorter sentences? Are mandatory sentences that strip judges of their judicial discretion ever acceptable? Do you think this inequity in sentencing and incarceration could affect how people view the justice system? Do you even see this as an injustice? Explain your position in essay form. (1-2 pgs, informal writing)