President Donald Trump's lawyers are gambling with the special counsel Robert Mueller as they prepare to duke it out with him in either Congress or the courts.

The defense plans to take an aggressive legal approach to Mueller if he seeks to compel Trump to testify in the Russia probe, but legal scholars are highly doubtful Trump's lawyers would be successful in fending off a grand jury subpoena.

Trump and his lawyers are also preparing for the possibility that Mueller will forego a court battle and instead release a report of his findings to Congress.

To that end, they've adopted a scorched-earth offensive against the special counsel that might just prove fruitful.

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If the special counsel Robert Mueller finds substantial evidence that President Donald Trump was involved in criminal activity, the fight could play out on one of two battlefields: Congress or the courts.

And in recent weeks, Trump's defense team has made it clear that it is prepared to duke it out with the special counsel in either arena.

'Going all in' on the legal front

The New York Times on Saturday published a lengthy memo Trump's defense attorneys John Dowd and Jay Sekulow sent to Mueller's office in January, and it sheds new light on the aggressive legal approach the defense will take if Mueller seeks to subpoena Trump to testify before a grand jury.

Saturday's memo is an opening salvo that previews how Trump's lawyers would fight the subpoena if it came to that.

In addition to claiming that Trump does not have time to testify, his lawyers also argued, citing the Constitution, that he cannot obstruct justice because he is the president.

Trump's actions, "by virtue of his position as the chief law enforcement officer, could neither constitutionally nor legally constitute obstruction because that would amount to him obstructing himself, and that he could, if he wished, terminate the inquiry, or even exercise his power to pardon if he so desired," the memo said.

"They're going all in," said Jeffrey Cramer, a former federal prosecutor in Chicago who spent 12 years at the Justice Department. "This memo has implications far beyond whether or not Trump sits for an interview. His lawyers are arguing here that he's not required to submit to an interview because he is the law and the law is him."

Meanwhile, the argument that Trump does not have the time to testify raised other questions.

Donald Trump plays a round of golf after the opening of The Trump International Golf Links Course on July 10, 2012 in Balmedie, Scotland. Ian MacNicol/Getty Images

"The president has the time to tweet every morning about what he watches on TV," Cramer said. "He has time to play golf at Mar-a-Lago every weekend. He has a block of 'executive time' built into his schedule so he can watch TV and tweet. But he doesn't have time to testify to the FBI?"

Legal scholars say that despite Mueller's reported threat to subpoena Trump, there are two reasons it is unlikely the special counsel will try to compel Trump to testify.

For one, a grand jury subpoena would almost certainly lead to a lengthy court battle, which both sides are keen on avoiding.

Moreover, current Justice Department policy states that a sitting president cannot be indicted, and Mueller may believe that for that reason, he does not have the authority to subpoena Trump either. Dowd and Sekulow's memo did not make much mention of that policy and seemed to rely more heavily on the constitutional argument that Trump cannot obstruct justice because as the chief executive, he has complete control over federal investigations.

Alex Whiting, a former federal prosecutor who is now a professor at Harvard Law School, pointed out that while the question of whether a president can be subpoenaed to testify in a criminal proceeding is unresolved, most legal experts believe he can and that a court of law would most likely come to the same conclusion.

He also pointed to the memo's bombshell admission that Trump dictated a misleading statement his son, Donald Trump Jr., put out in response to reports about his meeting with a Russian lawyer at the height of the campaign.

Sekulow and other Trump spokespeople denied Trump had any role in putting out the statement on at least five different occasions before his defense team admitted to his involvement in January's memo.

Whiting noted that the lawyers' arguments "only underscore the various conflicts in the evidence and the shifting stories from Trump and the White House," demonstrating the need for Mueller to interview "the person at the center of the inquiry."

Overall, the memo lays bare the Trump team's gamble when it comes to Mueller.

"They're hoping Mueller doesn't want to drag this out in the courts and that he'll agree to something lesser, like a two-and-a-half hour interview that isn't under oath," Cramer said. "They're playing poker with Mueller, hoping he'll settle for their terms, which he won't."

He added that the most likely outcome if the issue goes to court is a compromise between the two sides involving Trump interviewing with Mueller under oath, and with his lawyers present, for a pre-determined amount of time.

Robert Mueller. AP Photo/J. Scott Applewhite

The court of public opinion

If Mueller decides against taking Trump to court, the alternative is preparing a lengthy and detailed report for Congress about Trump's actions. According to The Washington Post, Mueller's office indicated to Trump's lawyers that it is leaning toward taking that path.

In the event that Mueller releases a report about his findings in the obstruction-of-justice case he has been building against Trump, experts say it will be a scathing indictment of the president similar to previous "speaking indictments" the special counsel has put out related to the Russia probe.

"Whatever report Mueller releases about Trump, if he found any evidence of criminal wrongdoing, you can bet he's not going to hold anything back," Patrick Cotter, a former federal prosecutor who has worked with members of Mueller's team, said in an earlier interview.

Indeed, Mueller's office pulled no punches when it indicted former Trump campaign chairman Paul Manafort and his longtime associate Rick Gates for charges related to tax and bank fraud, money laundering, conspiracy against the US, and failure to register as foreign agents.

The charging documents laid out Manafort's and Gates' alleged criminal behavior in stark detail, and they also included minutiae about the two men's financial dealings and communications with suspicious actors linked to the Russia probe.

Prosecutors took a similar approach when Mueller's office indicted 13 Russian nationals and three Russian entities in February for conspiring to sway the election via a social media disinformation campaign. In addition to devoting several pages to the alleged criminal activity, prosecutors painted an intricate picture of how the Russians carried out their scheme, including particular dates, communications, and social media accounts that were used.

In a scenario involving a report about the president, Trump's lawyers understand that it will be crucial to establish that Trump is more credible than the special counsel. To that end, they've embraced a scorched-earth offensive against Mueller and the top ranks of the Justice Department.

"As only one of two people left who could become President, why wouldn't the FBI or Department of 'Justice' have told me that they were secretly investigating Paul Manafort (on charges that were 10 years old and had been previously dropped) during my campaign?" Trump tweeted on Sunday. "Should have told me!"

Earlier this week, he fired off a barrage of tweets this week to his 52 million Twitter followers, unloading on Mueller and the "13 Angry Democrats" he accuses, without evidence, of embarking on a political "witch hunt" against him and his associates.

Giuliani acknowledged Trump's intentions behind his tweets, telling Business Insider this week, "Our jury is the American people. If they decide that the president is being badly treated, there's no way any Congress will impeach him."

"The things Trump says, it's like a mantra — and the more he says it, the more people believe it," Cramer said. "And now we're in this alternative universe where on one side you've got a three-time bankrupt game-show host and real-estate developer, and on the other side you've got Bob Mueller. Really, this is a close call? But apparently it is."