(CNN) Members of Congress reacted Friday with mixed reviews -- some sharply critical -- of Attorney General Jeff Sessions' new directive that could potentially ramp up criminal charges in cases involving nonviolent drug crimes.

Members of both parties have been pushing for reform in this area in recent years . Sen. Rand Paul, R-Kentucky, has been one of the most vocal Republicans leading the effort and was critical of Sessions' new policy.

"Mandatory minimum sentences have unfairly and disproportionately incarcerated too many minorities for too long," he said in a statement. "Attorney General Sessions' new policy will accentuate that injustice. Instead, we should treat our nation's drug epidemic as a health crisis and less as a lock-'em-up-and-throw-away-the-key problem."

Meanwhile, Sen. Tom Cotton, R-Arkansas, offered praise for Sessions' new action, saying "law enforcement should side with the victims of crime rather than its perpetrators."

"This policy is simply common sense and will help reduce crimes and drugs in our neighborhoods," he said in a statement.

For Democrats, the responses appeared almost uniformly negative. Sen. Dick Durbin, D-Illinois, argued that such a policy will cause costs to skyrocket and create more separation in families in ways that could have a "destructive effect" on communities.

He also speculated that the announcement was made at a time at which it would get little media coverage.

"It's no coincidence that the Sessions memo was quietly signed on the same day the President was making major headlines for firing FBI Director Comey because of his investigation of Trump — this policy is unjust and unwise and can't withstand even minimal public scrutiny," Durbin said. Sessions held a news conference on the new policy earlier Friday and Trump has said he decided to fire Comey because the President thought he was doing a bad job and for being a "showboat."

Sen. Kamala Harris, D-California, said in a statement that Sessions is trying to revive the "war on drugs," which she said "treated drugs, addiction and substance abuse as a crime instead of as a public health issue."

"Jeff Sessions wants to turn back the clock on the progress we've made, and we're going to have to fight and speak out against it," she added.

Sen. Bob Casey, D-Pennsylvania, tweeted flatly that "this is wrong."

This is wrong. DOJ should focus on prosecuting violent criminals, not nonviolent drug offenders. We must reform our criminal justice system. https://t.co/JuD4BDndlc — Senator Bob Casey (@SenBobCasey) May 12, 2017

"DOJ should focus on prosecuting violent criminals, not nonviolent drug offenders. We must reform our criminal justice system," he added.

During the Obama era, federal prosecutors were instructed not to charge someone for a drug crime that would trigger a mandatory minimum sentence if certain specific factors were met: (a) the relevant conduct didn't involve death, violence, a threat of violence or possession of a weapon; (b) the defendant wasn't an organizer, leader or manager of others within a criminal organization; (c) there were no ties to large-scale drug trafficking operations; and (d) the defendant didn't have a "significant" criminal history, such as prior convictions.

All of those charging factors are now gone under Sessions' reign -- not surprising, as he has previously telegraphed his desire to prosecute more federal cases generally.