After 24 days dissecting public acts and private pain, closing arguments were scheduled for Friday in the federal corruption trial of former Virginia governor Robert F. McDonnell and his wife, Maureen.

The final pitches to the jury are expected to be lengthy, with closings by the defense teams for each of the McDonnells bookended by presentations by prosecutors.

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Before jurors can begin deliberations, however, U.S. District Judge James R. Spencer must instruct them on the rules of law they must follow and apply to the weeks of testimony and evidence.

The instructions are in essence the playbook for how to reach a decision on whether the McDonnells sold the influence of the governor’s office to a Richmond executive who lavished their family with more than $177,000 in gifts and loans as he tried to bolster and burnish his struggling dietary supplement business.

On Thursday, Spencer shared his proposed instructions with the trial teams, who then pressed to have him add or delete information that would bring the instructions closer to their views of the case.

The language Spencer settled on won’t be known publicly until he reads it for jurors in court, although he told lawyers that he would have final copies for them late Thursday to assist them as they prepare their closing arguments.

The wrangling over wording can appear esoteric but is critical because it is how a judge tells the jury “here is what I think is the framework in which you have to operate. It’s significant especially in white-collar cases,” which can be more nuanced than street crimes, said Nancy Gertner, a former federal judge on the faculty at Harvard Law School.

To win convictions on the public corruption charges, prosecutors must prove that the couple performed or agreed to perform “official” acts in exchange for Williams’s largesse.

In last-minute appeals to Spencer in open court Thursday, defense attorneys expressed concerns that under the instructions he was then considering, the jury could convict the McDonnells of trading gifts and loans for conduct that does not rise to the level of official government acts.

The debate suggested that Spencer was leaning to a definition prosecutors had previously suggested. An official act, the government had argued, should “include acts that a public official customarily performs, even if those actions are not described in any law, rule, or job description.” They added that the official “need not have actual or final authority over the end result sought by a bribe payor so long as the alleged bribe payor reasonably believed the public official had influence, power, or authority over a means to the end sought by the bribe payor.”

Noel Francisco, an attorney for the former governor, took particular aim at the judge’s definition of an official act, saying it was “impermissible and inappropriate” and would allow McDonnell to be convicted for “things as innocuous as arranging a meeting.”

The issue has been a key one since charges were filed against the couple in January. The McDonnells face 14 criminal counts.

Francisco asked for explicit language that “there has to be a payment made in exchange for a promise to perform a specific official act,” arguing that the “generalized hope of some unspecified future benefit is not a bribe.”

Prosecutors raised comparatively fewer points.

Assistant U.S. Attorney Ryan Faulconer argued that Spencer should remove an instruction that seems to imply that the jury can only convict Maureen McDonnell on some public corruption counts if it also finds her husband guilty.

Faulconer also asked the judge to clarify an instruction that would exonerate the former governor if he acted in “good faith,” and sought to add language that would tell jurors that they could find him guilty if he acted on an “as-needed basis” for Williams in exchange for his generosity, rather than performing specific acts for specific gifts.

“Jury instructions are almost always way more critical to the outcome of a case than people believe. Especially in a case like this one,” said Paul Rothstein, law professor at Georgetown University Law Center.

Part of the case turns on deciding what connection, if any, there was between favors Williams gave and any government favors McDonnell may have given. But “the law is a little vague on the precise nature of the connection so how the judge describes it to the jury is critical,” Rothstein said.

The arguments Thursday over language seemed aimed at restoring verbatim some of the wording each side had previously suggested in instructions they’d proposed in more than 200 pages of court filings in July.

When judges deliver their instructions to jurors, the jury is told it must follow the law that the judge has just defined for them. “That makes this a very powerful moment in a case,” said Richard Kelsey, assistant dean of the George Mason University School of Law. “It’s like getting the gospel handed down to you.”

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