WASHINGTON With a blessing from Donald Trump a politician so tough on crime he still thinks the Central Park Five are guilty Congress could pass a bill before the end of the year to make the criminal justice system a little less harsh and a little less racist.

Theres just one problem: Senator Tom Cotton.

Thousands of people will be released within weeks or months of a bill like this passing, the Arkansas Republican told HuffPost. I think its a danger to public safety and not sound policy.

The bill is called The First Step Act . It aims to reduce recidivism and would shorten some prison sentences. Both Republicans and Democrats support the bill. The American Civil Liberties Union likes it, and so does FreedomWorks, the conservative lobbying group associated with the Tea Party movement.

But Cotton is doing everything he can to sour Republicans on the legislation. He railed against the bill during a lively Tuesday lunch meeting with his Republican colleagues, warning them they would be blamed if any recently released prisoner commits a new crime.

He was the guy who was most sharply against the bill, Sen. Lindsey Graham (R-S.C.) told HuffPost. Hes saying, Someones going to get out; were all going to lose our seats.

And since Senate Majority Leader Mitch McConnell (R-Ky.) has said he doesnt want to put the bill up for a vote if it divides his party, Cotton could get his way.

Its too bad that I agree with Cotton 90 percent of the time, and on something like this that I think is very strong on law enforcement [we dont], Senate Judiciary Committee Chairman Chuck Grassley (R-Iowa), a major proponent of the bill, said Tuesday.

Weve just gotta keep working, and were going to have to overcome Cottons opposition, he added.

McConnell has said the Senate might not have time to consider the bill before it adjourns for the year, especially with the looming lapse in government funding in the next few weeks and several other must-pass items on the agenda. Opponents like Cotton are likely to drag out the process on the floor as much as possible which could eat up a week or more.

Proponents of the effort, however, fear that if the Senate doesnt take up the bill in the lame-duck Congress, its chances of passage next year may be substantially harder with Democrats in control of the House. Newly elected Democratic members in the House may add more liberal provisions that could bog down the bill in the Senate, for example.

If it doesnt happen this year, its probably never going to happen, Graham told reporters on Tuesday.

Sen. Tim Scott (R-S.C.), another supporter of the bill, estimated on Tuesday that 21 Republicans are firmly on board with the measure. Another five GOP senators, he said, are soft yeses. The bill has 11 Democratic co-sponsors.

Federal inmates accounted for fewer than 200,000 of the more than two million Americans locked up in prisons and jails in 2016, according to the latest numbers from the Bureau of Justice Statistics . The federal prison population skyrocketed from just 25,000 in the early 1980s thanks to new mandatory minimum sentences and the elimination of parole. In recent years the number of inmates has gradually declined.

One of the most notorious mandatory minimums of the 1980s established a five-year sentence for offenses involving 500 grams of cocaine or just 5 grams of crack cocaine meaning the penalty for crack was 100 times harsher than the penalty for regular powder cocaine, even though crack is nowhere near 100 times more harmful. The harsher penalty overwhelmingly fell on African-Americans, who comprise 38 percent of federal prisoners but only 13 percent of the overall U.S. population.