Sen. Ted Cruz, R-Texas, had the voice of a liberal and a libertarian when he wrote a piece for the Brennan Center for Justice in April that ripped the federal criminal justice system on three fronts — “overcriminalization, harsh mandatory minimum sentences, and the demise of jury trials.” “Draconian mandatory minimum sentences,” he wrote, can produce sentences that far outweigh the crime, especially for “nonviolent drug offenders.”

The Ted Cruz who wrote that piece — and co-sponsored the Smarter Sentencing Act of 2015 with Sens. Mike Lee, R-Utah, and Dick Durbin, D-Illinois, — may not be familiar to those following Cruz on the GOP presidential primary trail. Lately the public has seen more of the Cruz whom New York Times columnist David Brooks faulted for “brutalism” in over-zealously prosecuting bad law as Texas solicitor general.

Which Cruz survives?

Mayhap the anti-reformer. In October, Cruz voted against the bipartisan Sentencing Reform Act, introduced by Sen. Chuck Grassley, R-Iowa, also with the support of Lee and Durbin, even though, Cruz supported “bolder mandatory minimum reforms than are in the Grassley bill,” according to Kevin Ring of Families Against Mandatory Minimums. The Grassley measure stands as an example of what a law-and-order Republican might do to acknowledge and lessen excesses in federal mandatory minimum sentencing. For that, Grassley got sideswiped by Cruz.

Cruz explained to his colleagues that he opposed the measure for two reasons — it would reduce sentences for “violent criminals” (read: drug dealers with guns) and also would do so retroactively. “Do we want to focus on disparities of nonviolent drug offenders or do we want to be releasing violent criminals?” Cruz asked. He also warned that if an inmate released by reforms ever hurt anyone, lawmakers “can fully expect to be held accountable” by voters.

Cruz’s warning turned out to be prescient. This month, a former federal crack offender was arrested for stabbing to death his former girlfriend, Erveena Hammonds, 32, and her daughters Breya, 7, and Anaesia, 10, in Ohio. The Columbus Dispatch reported that accused killer Wendell Louis Callahan had his prison sentence reduced because of reforms designed to reduce the sentencing disparity between federal crack and cocaine offenses. “Three people, including two children, are dead today because of early release from a duly imposed, lawful and fully deserved federal drug trafficking sentence,” an outraged Georgetown law professor William Otis wrote on the Crime and Consequences blog. Politico reported GOP opponents seized upon the crime in an effort to derail the Grassley bill.

In his State of the Union address, President Obama said that he hoped to sign a bipartisan criminal justice reform bill this year. Senate Majority Leader Mitch McConnell is working on it, but that’s no easy feat, noted spokesman Don Stewart, when lawmakers like 80 percent of the measure, but really hate something in the other 20 percent.

The bill’s biggest hurdle is the 2016 presidential race. Before Cruz voted against the Grassley bill, Donald Trump became the GOP front-runner with his tough talk and disdain for mercy. After the bill passed the Senate Judiciary Committee, terrorists attacked in Paris, then in San Bernardino. In this uncertain election year, the public craves safety.

I supported the 2009 Fair Sentencing Act because the 100-1 sentencing disparity for crack offenders popped out “sledgehammer prison terms even for nonviolent and first-time offenders.” I’ve written about low-level offenders sent away for decades, even life, for nonviolent offenses. That’s not justice.

Some reformers will tell you off the record that when you let people out of prison to re-balance sentences, it’s inevitable some will re-offend. They don’t understand that the Hammonds may be the Laquan McDonalds of sentencing reform. It turns out that alleged killer Callahan was free because courts reduced his 150-month sentence to 100 months as part of federal crack sentencing reform and freed Callahan in 2014. But why? Callahan was not a nonviolent offender. His 2006 conviction was for a cocaine trafficking with a firearm. In 1999, Callahan was convicted in connection with a nonfatal shooting. The Columbus Dispatch reports that while his 2006 federal case was pending, police arrested Callahan for beating and choking Hammonds.

A federal judge would have to approve the sentence reduction after hearing from prosecutors, former federal prosecutor William Otis told me; if the judge “knew about those facts and then said anyway this man poses no danger to the public, that can’t be great.”

President Obama should direct his Justice Department to investigate Callahan’s release to prevent another tragedy. If reformers instead choose to circle the wagons, then their crusade will fail.

Cruz can do the easy thing and walk away from his pre-Trump call for curbing federal prosecutorial abuses. Or he can stick out his neck for justice for all. That’s a principled stand, but then Cruz likes to say he puts principle first.

Email Debra J. Saunders at dsaunders@sfchronicle.com.