Attorney General Jeff Sessions took aim on Wednesday at a number of criminal justice reform proposals that are being spearheaded by prominent Republicans in Congress in a letter he sent to Senate Judiciary Chairman Chuck Grassley (R-Iowa), according to CNN.

What's the background?

Congress is set to debate a number of proposals for criminal justice reform that stalled in the waning days of former President Barack Obama's tenure, but which have achieved bipartisan momentum in recent days and weeks. Among these bills, the Sentencing Reform and Corrections Act would make significant reductions in mandatory minimum sentences, particularly for drug offenses.

Additionally, Sens. Rand Paul (R-Ky.) and Kamala Harris (D-Calif.) have led a separate bipartisan push for bail reform.

The bills are collectively designed to increase fairness and flexiblity in the criminal justice system, and to reduce the United States prison population — a significant portion of which is held there on bail awaiting trial.

Conservative and libertarian think tanks have become increasingly active in the criminal justice reform movement recently, with the end result being that an increasing number of traditionally conservative members of Congress — including Grassley and Sen. John Cornyn (R-Texas) — have signed on to co-sponsor various criminal justice reform bills.

Sessions, however, holds more traditional views on law enforcement and finds himself increasingly at odds with the Senate Republican caucus as a result. When Sessions announced modifications to the Obama-era policy, which allowed legalized recreational marijuana to flourish in places like Colorado, Sen. Cory Gardner (R-Colo.) reacted furiously, accusing Sessions of breaking his word and promising to put a hold on all Department of Justice nominees until Sessions reversed his position. When Sessions issued instructions to prosecutors to always charge suspects with the most serious provable offenses, he was harshly criticized by many Republicans, including Rand Paul. And Sessions faces increasing criticism even from Republican senators who have criticized his handling of the Justice Department for completely unrelated reasons, including his decision to recuse himself from the probe into potential collusion between the Russian government and the Donald Trump presidential campaign.

Nonetheless, Sessions made his displeasure known with the latest comprehensive criminal justice reform efforts, which are sponsored by Grassley, by telling Grassley that the act "would reduce sentences for a highly dangerous cohort of criminals, including repeat dangerous drug traffickers and those who use firearms, and would apply retroactively to many dangerous felons, regardless of citizenship or immigration status... In my opinion, if passed in its current form, this legislation would be a grave error."

In a terse tweet, Grassley dismissed Sessions' criticism of the bill, essentially telling Sessions to leave the bill writing to Congress:

Although the bills do enjoy bipartisan support, it is unclear what their chances of passage are or whether President Donald Trump will throw his weight behind their passage. Congress is expected to remain focused on immigration-related debates for the foreseeable future as the March 5 deadline for the expiration of the Deferred Action for Childhood Arrivals program approaches.