I need to prepare for Christmas dinner with my lib family and need well sourced arguments, since I will attack people from the left, the side of the political spectrum that needs sources for every claim. Anyway, sources like The Intercept or Jacobin are still acceptable.
Here's a good one if they try the "but she's said/done some things to stop mass incarceration" line:
So whatever's currently being done is woefully insufficient.
And if they say a 50% reduction in the prison population sounds aggressive and unrealistic, point out that a reduction of this magnitude would still leave us with about 2.5 times the per-capita prison population of the U.K.