The controversy over the lack of sentencing reform in the bill has underscored sharp divisions among Democrats and other advocates of sweeping criminal justice reform.
Republicans who control the Senate indicate a vote is not likely there any time soon. Instead, Senate Judiciary Chairman Chuck Grassley, an Iowa Republican, is continuing to push for the bipartisan legislation he wrote with Illinois Democratic Sen. Dick Durbin that includes sentencing reforms that the White House are opposed to.
The bill that passed the House on Tuesday would impose a series of changes to the Bureau of Prisons, including expanding access for some prisoners to programs geared at reducing recidivism, offering eligible inmates chances to earn time out of prison and solidifying federal prison rules for the treatment of women behind bars. The bill from Grassley and Durbin combines similar prison reform components with a rollback of some mandatory minimum sentence requirements that proponents say wrongfully forces judges' hands and leads to longer than needed sentences.
Durbin said his fellow Democrats who might be inclined to accept the prison reform bill alone should instead focus on the policies that put high levels of people into prison to begin with.
"This slightly opening the exit door for those to leave prison ignores the obvious: we are filling it from the front end," Durbin said.
As for the chances of a bill touching sentencing reform coming together in the Senate, Durbin pointed to Senate Majority Leader Mitch McConnell.
"It is entirely up to McConnell," Durbin said.
Durbin is joined in his opposition to the House bill by many of his colleagues, including California Democratic Sen. Kamala Harris and New Jersey Democratic Sen. Cory Booker, both prominent advocates of criminal justice reform who were recently seated on the judiciary committee.
"The component that is about what we do with incarcerated people and people in prisons is an important one," Harris told CNN. "But it has to be coupled with sentencing reform, which is one of the biggest reasons that we have this mass incarceration problem, which we have as a country."
They likewise have the backing of several prominent outside groups, including the ACLU, the Leadership Conference on Civil and Human Rights and the NAACP Legal Defense Fund.
The bill's opponents also criticize it on the substance, with the federal correctional workers' union reaching out to Congress urging its defeat.
Eric Young, president of the Council of Prison Locals, told CNN that some provisions in the bill would otherwise stretch the Bureau of Prisons too thin, and said in addition to sentencing reform to reduce the federal inmate population, the federal prison system needs more personnel.
"We don't have the staff," Young said. "We don't have the money. If you're going to be a hardliner on keeping people incarcerated with more sentencing, if you're going to be a rehabilitation proponent for inmates, offenders that are incarcerated in our care, it requires resources be provided to us to fulfill whatever those mandates are."
Similarly, Virginia Democratic Rep. Bobby Scott said on Tuesday that he had problems with the bill both on substance and the process that led to its passage, saying there are "several problems" with the legislation and that "it is obvious that experts had little to do with drafting the bill."
Nevertheless, he came out in its favor, saying he guessed no prisoner would be left "worse off" and "many may be significantly better off."
But the House bill has key Democrats firmly in its corner, along with its own slew of advocacy groups.
The House legislation is co-sponsored by New York Democratic Rep. Hakeem Jeffries, and its companion legislation in the Senate has the support of Rhode Island Democratic Sen. Sheldon Whitehouse, who also supported the comprehensive approach.
Jeffries, speaking to reporters on Monday, said while he supported sentencing reform, the position of the Trump administration made it clear only the prisons legislation could be signed into law.
"Once we do our job and pass the First Step Act, then it will fall upon the Senate to evaluate what legislation can actually pass that chamber and be sent to the President's desk," Jeffries said ahead of the vote. "It's clear that the First Step act is the bill that the White House supports and can be signed into law."
In addition to the White House, the bill has the backing of Families Against Mandatory Minimums and #Cut50, a group co-founded by liberal CNN commentator Van Jones.
Jones has taken issue with Democrats and other advocates who have come out against the bill, saying this week that "this everything or nothing theory has failed people behind bars."
He also accused some opponents of playing politics with the issue and said he had no problem finding himself on the same side as Trump's son-in-law and adviser Jared Kushner or the powerful Koch network, which supports the bill.
"You have some people, their political agenda is to deny Trump a win, even if that means you're denying 200,000 federal prisoners from winning," Jones said. "That's a part of the calculation for some of these groups."
'Don't see a bright future for it'
Grassley, Durbin and other members of the Senate Judiciary Committee huddled for several minutes on the Senate floor with McConnell on Wednesday, along with Texas GOP Sen. John Cornyn, the number two Republican and a member of the committee who is advancing legislation mirroring the House bill.
Following the huddle, Grassley said he continued to want his bill and indicated McConnell would avoid a floor debate until the impasse was nearly solved.
"I don't think he's gonna bring anything up unless he knows he can get it done in two or three days," Grassley said.
Tim Scott, a Republican from South Carolina who has worked extensively in the Senate on efforts to overhaul the criminal justice system, told CNN he met with Kushner about two weeks ago and spoke with him about the House proposal, but said a key concern members have had is the fact that it does not address sentencing.
"I don't see a bright future for it in the Senate," Scott said of the House's proposal.
Speaking to reporters on Tuesday, Cornyn said negotiations need to produce "a bill of consensus" before a floor vote can take place.
"We need to do the hard work to build that consensus because right now we don't have it because obviously some people want to do more -- like Sen. Durbin and Sen. Grassley and some people have some