Authors of a criminal justice reform bill pending in the Senate rolled out a new version late Wednesday, with changes reflecting some but not all bill critics' concerns.

After weeks of stonewalling, Senate Majority Leader Mitch McConnell (R., Ky.) announced Tuesday that he would allow a vote on the FIRST STEP Act. The bill had previously had solid backing with Senate Democrats, but struggled to gain traction with Republicans—indicating that were it to pass, it would do so without the support of a majority of McConnell's caucus.

Now a number of Republicans have come out in favor of the bill, citing changes they expect to see in the final bill text which will ameliorate their concerns about public safety. Prominent names who have flipped to the yes column include law-and-order conservatives such as Sen. Ted Cruz (R., Texas) and Sen. David Perdue (R., Ga.).

The Senate Judiciary Committee, led by FIRST STEP author Sen. Chuck Grassley (R., Iowa), late Wednesday released a new version of the bill expected to be brought to the floor. This revision of FIRST STEP will make a number of substantive changes, addressing some but not all of critics' concerns.

First and foremost are alterations to the bill's central component, the time credit system. The system allows federal offenders to earn "time credits" for participating in recidivism-reduction programming, between 10 and 15 days of credit per 30 days of participation. Those credits can be used by prisoners who have "demonstrated recidivism risk reduction" or "maintained a minimum or low recidivism risk" to be released early to a halfway house or supervised release.

The bill contains a list of offenses that would preclude an inmate from being able to access the time credits. Many critics—including Republican Senators and multiple Sheriffs groups—have argued that this list was insufficiently lengthy, and under-inclusive of violent crimes.

Cruz, in announcing his support for the bill, claimed to have secured support for an amendment that would add a number of offenses to the exclusion list. The announced revisions to the exclusions list do not perfectly match those included in a version of the Cruz amendment seen by the Free Beacon, include offenses like arson, rioting in a correctional facility, and female genital mutilation.

The revisions also expand the number of federal drug traffickers excluded from time credits, adding all fentanyl dealers (not just top-level ones) and top-level methamphetamine dealers—the latter an addition instigated by recent supporter Sen. Steve Daines (R.), whose state of Montana is in the midst of a meth crisis.

The revised version of the bill will also alter the expanded safety valve provision in its original form. Under current federal law, individuals with a single minor, non-violent conviction can have mandatory minimum sentences waived by their sentencing judge. FIRST STEP would have altered this so-called "safety valve" in two ways: expanding the length of past criminal history allowable for safety valve eligibility, and creating a safety valve to the safety valve by allowing judges to waive mandatory minimums for non-violent drug offenders altogether if they explained why in writing.

This latter provision will be struck from the new bill, a change supported by Perdue, Cruz, and others; expanded access to the safety valve, however, remains.

While these two changes may sway senators on the fence, it is unclear if they will garner the support of more hardcore opponents. Although the official summary of the bill claims to specifically address the concerns of the National Sheriffs' Association—a vocal law enforcement critic of FIRST STEP—it falls short of several requests in the group's November letter.

For example, the NSA and its peers sought to have the expansion of the safety valve removed altogether, while the bill will only remove part of it. The NSA also sought to have supervised release struck as an option, preferring time credits only be expended on release to a halfway house or home confinement. But the new bill will only constrain who has access to supervised release, limiting it to low- and minimum-risk offenders.

Sen. Tom Cotton (R., Ark.), FIRST STEP's fiercest opponent, was not satisfied by the proposed revisions. He noted in a release that a number of federal violent offenders remained uncovered by the bill, including those convicted of bank robbery with a dangerous weapon, assault against a child, and carjacking with intent to cause death.

Although it has McConnell's support, it is unclear at this point when or if FIRST STEP will make it to the floor. Sen. John N. Kennedy (R., La.) said Wednesday that he would block unanimous consent to proceed to a vote on Thursday, saying that "he and the country need more time to digest the bill." Such a block means it is unlikely that the bill will get a full vote before next week.

Cotton and Kennedy are also working on an amendment to the bill to exclude even more violent offenders from time-credit eligibility, the Washington Post reported.