Attorney General Jeff Sessions has announced he is directing federal prosecutors to pursue the most severe penalties possible for drug crimes.

Civil rights groups and Republican legislators oppose the sentencing changes, The Washington Post reports.

Sessions sent a memo to prosecutors that overturned former Attorney General Eric Holder’s instructions to avoid charging certain defendants with the most serious crimes that carried the longest sentences.

“We are returning to the enforcement of the laws as passed by Congress, plain and simple,” Sessions said. “If you are a drug trafficker, we will not look the other way, we will not be willfully blind to your misconduct.”

The Obama Administration favored more lenient and flexible drug sentencing laws. The federal population declined during the Obama years, for the first time in a generation.