We have. I mean, there's the fair sentencing act that was signed in 2010 among other reforms.
Wrt this, McConnell blocked it because it would have been seen as a victory for Obama. Why is it so hard for some of you to see what's going on here?
Why the Senate Couldn’t Pass a Crime Bill Both Parties Backed
WASHINGTON —
A major criminal-justice overhaul bill seemed destined to be the bipartisan success story of the year, consensus legislation that showed lawmakers could still rise above politics.
Then the election, Donald J. Trump’s demand for “law and order” and a series of other political calculations got in the way.
Senate Republicans divided on the wisdom of reducing federal mandatory minimum sentences. Other Republicans, unhappy that President Obama was reducing hundreds of federal prison sentences on his own, did not want to give him a legacy victory.
...
Mr. Cornyn concedes the tumult of this election year was a major factor given sharp disagreement among Senate Republicans reflected in the decision by
Senator Mitch McConnell, Republican of Kentucky and the majority leader, to not allow a vote on a proposal most believe would pass easily.