"It's always safer in a life-or-death situation for a judge to grant a stay, hear a full recounting of the evidence, and then let an execution proceed," he said. "An execution is the ultimate final act of the judicial system, and judges are very reluctant to let one go forward if there are any open questions at all."
A Close Look at the Documents
Much of the judge's decision will be based on just what is in the thousands of pages of previously undisclosed documents at the heart of the controversy, he said.
"No neutral party has looked at these documents yet. We've only heard spin from the government, and spin from the defense," he said. "Judge Matsch may give a signal of how significant he thinks these documents really are, and that's going to be very important."
In the end, Lane says Matsch will be ruled by his desire to do everything possible to ensure the integrity of the legal process — even for Timothy McVeigh, who has been reviled and vilified for the 1995 attack that left 168 dead, including 19 children, and hundreds injured.
"Judge Matsch would not hesitate to vacate Tim McVeigh's death sentence if he believes the withheld evidence would have possibly affected the outcome of the penalty phase determination of death," said Lane.
McVeigh is scheduled to die on June 11. ABCNEWS' Steve Walsh, Bill Redeker and ABCNEWS Radio contributed to this report.