In Texas and Illinois, recent controversies have exposed our broken criminal justice system. Mounting evidence indicates that Texas Governor Rick Perry ordered the wrongful execution of Cameron Todd Willingham in 2004 and has subsequently tried to cover up the details of the case, recently dismissing three experts on the state’s Forensic Science Commission forty-eight hours before they were set to examine the evidence. Willingham’s case has rightly generated national headlines, and another case of prosecutorial overreach is unfolding in Illinois.

On the evening of September 15, 1978, a white security guard named Donald Lundahl was murdered in a robbery gone awry in a racially fraught southern suburb of Chicago. Police fingered Anthony McKinney, an 18-year-old African-American with no criminal record, as the killer. The prosecution sought death by lethal injection; the judge sentenced McKinney to life in prison.

McKinney has long maintained his innocence. Based on newly uncovered evidence, there’s strong reason to believe that he has spent thirty-one years in prison for a crime he did not commit.

When it comes to capital punishment, Illinois differs from Texas in one important respect: in 2000 the Land of Lincoln’s Republican governor, George Ryan, issued a moratorium on the death penalty, and in 2003 he granted clemency to all death-row inmates. Ryan announced his decision at Northwestern University, citing the work of Northwestern journalism professor David Protess and his students at the Medill School of Journalism, who had uncovered evidence that helped free five wrongly convicted men from death row.

In 2003 Protess and his students began examining McKinney’s case. Over three years of painstaking reporting, they unearthed startling new evidence: the prosecution’s two main witnesses, 15 and 18 at the time of the trial, recanted their testimony during interviews with the students, claiming they were beaten by the police and intimidated into doctoring the facts; McKinney alleged that he was beaten with a pipe by a detective with a history of police brutality before signing a sham confession; TV logs proved that both witnesses were watching a boxing match at the time of the shooting and thus could not have seen the murder; an ex-gang member, Anthony Drake, confessed on tape to being at the murder scene, named two perpetrators and said McKinney was not involved; current and former residents of the neighborhood confirmed they heard Drake and two other suspects confess to Lundahl’s murder.

In 2006 the Medill Innocence Project turned over its findings to the Center on Wrongful Convictions at Northwestern’s law school. The center shared the evidence with the Cook County State’s Attorney’s Office, which began an internal investigation the following year. After more than a year of delay by the state, the center filed a postconviction petition on behalf of McKinney in October 2008, calling for a new trial or his immediate release. Following her election that November as Cook County State’s Attorney, hardline career prosecutor Anita Alvarez fought the discovery of new evidence, and in May she issued a sweeping, unprecedented subpoena ordering Protess to hand over all material related to the McKinney case–including students’ private memos and grades. Alvarez insultingly suggested that students might receive better grades for uncovering exculpatory evidence and claimed that Protess and his students were “investigators,” not journalists, and thus not subject to the Illinois shield law. (A proposed federal shield law circulating in Congress, while commendable, would affect only a minority of subpoenas, protecting confidential sources but failing to cover reporters’ unpublished work.) Apparently Alvarez has never heard of investigative journalism.

Judge Diane Cannon, a former career prosecutor in Cook County, approved the subpoena, which Protess is challenging in court. “Prosecutors should be more concerned with the wrongful conviction of Anthony McKinney than with my students’ grades,” he says.

The state’s subpoena, wielded to stall justice and intimidate those who seek it, sets a terrible precedent. Lawyer Barry Scheck says that in his seventeen years at the Innocence Project in New York, he’s never seen a subpoena of this nature directed at journalists or lawyers. Concludes Jonathan Turley, a constitutional law expert at George Washington University, “It creates an enormous chilling effect that’s positively glacial.”

Judge Cannon will soon rule on the validity of the state’s subpoena. We urge her to throw it out and order a prompt evidentiary hearing. The kind of difficult reporting undertaken by the Medill Innocence Project should be celebrated, not undermined. It’s shocking that the state would rather keep an innocent man behind bars than admit a mistake.

Nine groups of student journalists from Medill have interviewed McKinney in prison. By their accounts, he’s a fragile and gentle man who’s battled severe depression during three decades of wrongful incarceration. “If the state had gotten its way,” Protess notes, “he would have been executed long ago.” A new trial, if not unconditional release, is long overdue. The truth won’t bring back Cameron Todd Willingham, but it can still free Anthony McKinney.