Wichita ? A judge turned away objections from prosecutors Tuesday, allowing confessed killer Scott Roeder the chance to build a defense to the slaying of a Kansas abortion provider based on his belief the action was justified to save unborn children.

Sedgwick County District Judge Warren Wilbert said it remains to be seen after the defense rests its case whether the evidence will suffice to instruct jurors that they can consider the lesser offense of voluntary manslaughter in the death of Dr. George Tiller.

“I am going to make every effort to try this case as a criminal, first-degree murder trial,” Wilbert said. “Admittedly Mr. Roeder’s beliefs may come into play and as a defendant he is entitled to present a defense.”

The judge said he would rule on a witness-by-witness, question-by-question basis as necessary throughout the trial on whether to allow jurors to hear specific evidence on Roeder’s beliefs about abortion.

“This is not going to be a debate about abortion,” Wilbert said, adding that attorneys will have to convince him at trial that any evidence offered in that regard will have to be part of what Roeder believed on May 31 when Tiller was killed.

Roeder has “a formidable and daunting task” to present such evidence, Wilbert said.

Tuesday’s hearing delayed the start of secret jury selection proceedings until Wednesday. Four media outlets, including The Associated Press, have asked the Kansas Supreme Court to overturn Wilbert’s decision to bar reporters from jury selection.

The facts of the case are not in dispute: As Sunday morning services were starting, Roeder got up from a pew at Wichita’s Reformation Lutheran Church and walked to the foyer, where Tiller and a fellow usher were chatting. He put the barrel of a .22-caliber handgun to Tiller’s forehead and pulled the trigger.

The 51-year-old Kansas City, Mo., man has publicly admitted to reporters and the court to killing Tiller. He also faces two counts of aggravated assault for allegedly threatening two ushers who tried to stop him from fleeing after the shooting. He has pleaded not guilty.

But what had been expected to be a straightforward trial was upended on Friday when Wilbert refused to bar Roeder’s lawyers from building the defense calling for a lesser charge of voluntary manslaughter. The judge prohibited only a so-called necessity defense that would argue Roeder should be acquitted because the doctor’s killing was necessary.

Kansas law defines voluntary manslaughter as “an unreasonable but honest belief that circumstances existed that justified deadly force.” A conviction could bring a prison sentence closer to five years, instead of a life term for first-degree murder.

The Kansas chapter of the National Organization for Women immediately condemned the judge’s decision, saying it opens the door for a society that would condone vigilantism and violence against abortion providers.

Prosecutors had filed a motion Monday saying the voluntary manslaughter defense is invalid because there is no evidence Tiller posed an imminent threat at the time of the killing.

The defense argued that the prosecution misinterpreted case law, saying any rulings about evidence should be made at the time of its presentation as is typical in any other criminal trial.

“This trial is going to be on TV, but it is not a TV trial — it is a real trial,” defense attorney Mark Rudy said.