Former Virginia Gov. Bob McDonnell and his wife Maureen make a statement in Richmond in January. (Steve Helber/AP)

The mudslinging started the day Robert F. McDonnell was indicted, when attorneys for the former Virginia governor compared prosecutors to the Roman emperor Caligula, trying to imprison people “for violating laws written in tiny lettering on a pillar too high to see.”

In filings since, McDonnell’s attorneys have accused prosecutors of having a “seriously flawed understanding of federal law,” suggested that they want to “unilaterally decide what evidence the defense, the judge, and the jury get to hear” and even sarcastically mentioned speed-reader Evelyn Wood in a dispute about documents.

Legal experts say the aggressive — even rancorous — motions are an effort to educate the judge and the public about McDonnell’s view of the corruption charges against him. Most of the defense requests — which, among other things, allege problems with the evidence that prosecutors have turned over and seek more specificity about the charges — are likely to be rejected, legal experts say.

But collectively, experts say, the motions begin to build a narrative of McDonnell’s version of events: that whatever he and his wife, Maureen, did for Richmond businessman Jonnie R. Williams Sr. and his struggling dietary-supplement company, Star Scientific, was not illegal. And the motions preview how the couple plans to fight the case at trial, arguing that the McDonnells’ actions were not “official” and thus not criminal.

“There’s a theme that’s developing here, and the theme is synonymous with what the former governor has said since the indictment was announced,” said Edward T. Kang, a lawyer at the firm of Alston & Bird and a former federal public-corruption prosecutor. “It’s like a chess game. You can’t just come out and say, ‘Oh, there were no official actions.’ You’ve got to build up to that.”

Added Scott Fredericksen, a lawyer at the Foley & Lardner firm: “It’s not completely settled. There are good arguments to be made here.”

That the McDonnells are vigorously fighting the charges is no surprise. Long before grand jurors in January returned a 14-count, 43-page indictment against the couple that alleges they lent the prestige of the governor’s office to Williams and his company in exchange for loans and gifts, McDonnell had insisted that he and his wife did nothing wrong. He rejected a deal that would have allowed him to plead guilty to one charge that had nothing to do with corruption in office while his wife avoided charges altogether, people with knowledge of the negotiations have said.

The vigorous legal wrangling by the McDonnells’ attorneys, though, hints that their relationship with prosecutors may have soured, legal experts say.

“These guys have had a lot of dealings back and forth,” said Kelly B. Kramer, a lawyer at Mayer Brown who specializes in white-collar defense work. “Part of what you’re seeing is a reflection of the actual relationship between the parties.”

On the day the McDonnells were indicted, defense lawyers filed two motions: one asking for the instructions that were given to grand jurors and another alleging that prosecutors did not understand their legal obligation to turn over evidence that could exonerate the couple.

The motion seeking grand jury information was a direct assault on the prosecutors’ case, unequivocally asserting that “Bob McDonnell is an innocent man” and accusing prosecutors of employing an “unprecedented legal theory that eradicates all limitations on federal bribery law.”

Legal experts said that even though such requests are rarely granted, they begin to convey to the judge what the sticking points may be. And when it comes time to write jury instructions — or rule on a motion to dismiss the indictment, expected to be filed soon — his familiarity with those points can be important, provided he doesn’t find the motions too frivolous, legal experts said.

“You may feel that, well, if he turns down these four or five, maybe we’ll get this one that we’ll really need,” said Peter R. Zeidenberg, a former federal prosecutor who is now at the DLA Piper law firm.

Prosecutors have not remained completely above the fray. After defense lawyers asked a judge to resume a civil suit by Star Scientific shareholders against the company — arguing that prosecutors’ request for a delay was meant only to keep quiet any possible unflattering evidence about Williams — prosecutors fired back with the sarcastic suggestion that McDonnell seemed to be asking for their help in his defense.

“In our adversary system, Mr. McDonnell’s multiple defense attorneys — not the Government or third parties — have the duty to mount his defense,” prosecutors wrote.

Jacob S. Frenkel, a former federal prosecutor who is in private practice at Shulman Rogers, said defense lawyers might be trying “to bait the government into taking steps that might open the government to an ultimate accusation of prosecutorial misconduct.” And at the very least, Frenkel said, the string of motions creates possible mechanisms to appeal.

“Every lost motion becomes an appellate issue,” he said.

In recent weeks, defense attorneys have highlighted what they allege are failures by prosecutors to turn over evidence — a popular tactic, experts said, in the wake of the botched corruption case against the late Sen. Ted Stevens (R-Alaska). In that case, judicial investigators found that federal prosecutors had concealed key evidence, among other missteps .

McDonnell’s attorneys wrote that a recent attempt by prosecutors to provide materials was so beset by technical problems that it was “the digital equivalent to dumping five-million loose-leaf documents on the floor.” Prosecutors acknowledged some technical slipups but said they had been rectified.

The most substantive of the defense motions, though, might have been the one filed late last month in which the lawyers requested more specificity about the “official actions” that the governor and his wife are alleged to have performed. Exactly what “official actions” are — and whether McDonnell and his wife performed them — is likely to be key to the case, according to legal experts and the motion itself.

Prosecutors allege that the McDonnells repeatedly asked Williams for loans and gifts of money, clothes, trips and private plane rides. The gifts and loans totaled at least $165,000.

In exchange, they say, Robert McDonnell promoted Star’s dietary supplement, Anatabloc, at various events; arranged meetings between Williams and senior state health officials; and worked with his wife to encourage state researchers to consider conducting trials of the product.

Those actions, experts said, are not as obviously “official” as vetoing a bill or making a Cabinet appointment.

Andrew T. Wise, a lawyer at Miller & Chevalier, said government attorneys will probably rely on their office’s experience prosecuting former congressman William J. Jefferson (D-La.), who was convicted in a bribery case in which he was accused of using his position to direct bribes relating to business ventures he helped arrange in Africa. Wise said what is considered “official” is a “murky area.”

“One of the problems in these public corruption cases is that I think sometimes these terms get defined as you go,” he said.

Peter H. White, a lawyer at the firm of Schulte Roth & Zabel, said that defense lawyers will probably argue at trial — as they have in some of their motions — that what McDonnell did for Williams was no different than what any politician does for campaign donors.

“While taking gifts at this level from this guy certainly is tawdry and, heck, maybe even should be illegal, I don’t know of another case where somebody has been prosecuted for hosting an event at the governor’s mansion,” he said.

In one motion, prosecutors argued that an action by a governor need not be “particularly substantial” to be official. They wrote in a filing Monday that they intended to prove official actions were taken, though they said the law requires only that they show such actions were promised.

A judge has scheduled a hearing on some of the motions for March 18 in Richmond. It is the first of several such hearings scheduled before the July 28 trial.

A spokesman for the Justice Department declined to comment. Attorneys for Robert and Maureen McDonnell did not return phone and e-mail messages from a reporter.