A former federal prosecutor thinks Mueller's quiet period before the midterms may not have been so quiet after all

• A former federal prosecutor wrote that although October was an outwardly quiet month in the Russia investigation, the special counsel Robert Mueller may have made his most significant move yet.
• Nelson Cunningham, the former prosecutor, wrote in Politico that based on a series of under-the-radar moves at two Washington, DC, courts, he believes Mueller may have moved to subpoena President Donald Trump.

• Jeff Cramer, another DOJ veteran, said Cunningham's theory was "consistent" with how he believed Mueller's decision to subpoena the president might play out.

• Trump and his attorneys denied that Mueller has issued a subpoena.

October was an unusually quiet month - at least publicly - in the Trump-Russia investigation.

The reasoning behind that, experts say, is that the midterm elections are just days away, and Justice Department guidelines prevent prosecutors from taking any overt actions that could influence the outcome of an election.

But Nelson Cunningham, a former federal prosecutor and Senate and White House aide, laid out compelling alternative evidence in Politico. He believes that special counsel Robert Mueller may have made his most significant move yet this month: subpoenaing President Donald Trump to testify before a grand jury.

The clues, Cunningham wrote, lie in a series of under-the-radar moves at the Washington, DC, district court and circuit court of appeals by lawyers working for Mueller and an unknown witness in the investigation:

• It started on August 15, when Rudy Giuliani, Trump's lead defense lawyer, said publicly that the president's lawyers are "pretty much finished with our memorandum opposing a subpoena."
• Giuliani's comment came amid months of back and forth between Trump's and Mueller's teams over the terms of a presidential interview. The two sides eventually agreed to a first round of written answers to questions about potential collusion between the Trump campaign and Russia.
• Trump's lawyers refused to agree to answer questions about obstruction, and Mueller reportedly relented but insisted he be allowed to ask follow-ups.

• The next day, prosecutors mounted a sealed grand jury case in the DC federal district court.
• A little over a month later, the judge in the case issued a ruling.
• Five days later, Cunningham wrote, one of the parties appealed the ruling to the DC circuit court of appeals, the second-highest court in the country.

From then, Cunningham wrote that three factors tipped him off to the fact that the sealed case may have to do with the president:

• The first was the speed with which the case was handled. Not only did the unidentified witness appeal the lower court's ruling almost immediately, but the appeals court also responded quickly. The court also set an accelerated briefing schedule, per Politico, and all the judges involved moved quickly to amend a procedural flaw in just under a week that typically would have taken "weeks or months" to resolve.
• The second factor Cunningham outlined was the witness's unusual decision to request a hearing before all 10 of the DC circuit court judges.
• The third factor was that Gregory Katsas, one of the judges on the panel, recused himself from the matter. Katsas was appointed to the court by Trump, and prior to joining the panel, he worked in the White House counsel's office as deputy counsel to the president.

"If Mueller were going to subpoena the president - and there's every reason why a careful and thorough prosecutor would want the central figure on the record on critical questions regarding his knowledge and intent - this is just the way we would expect him to do so," Cunningham wrote.

Jay Sekulow, one of Trump's defense lawyers, denied Politico's story on Wednesday, telling The New York Times there was "no subpoena issued and there is no litigation."

Trump later told reporters the same.

Read more: What 3 past presidents did when they were subpoenaed, and what could happen if Mueller tries to make Trump testify

A presidential subpoena would likely kick off a lengthy constitutional battle that would go all the way to the Supreme Court.

Current DOJ policy states that a sitting president cannot be indicted. Trump's lawyers have argued that if he cannot be indicted, he also cannot be subpoenaed.

DOJ veterans and Mueller's former associates have described him as a by-the-books prosecutor, adding that he is unlikely to go against DOJ guidelines on the issue of indictment.

But the move may not be completely off the table.

In May, The Washington Post reported that during a negotiation in March, Mueller threatened to subpoena Trump to testify before a grand jury if he did not agree to a voluntary interview.

Giuliani told Business Insider in August that he plans to fight a potential grand jury subpoena "all the way to the Supreme Court."

Jeff Cramer, a longtime former federal prosecutor who spent 12 years at the DOJ, said Cunningham's theory was "consistent" with how he believed Mueller's decision to subpoena the president might play out.

"I can't imagine Mueller's going to back away from the fight," he said. "If the president ultimately says, 'No, I'm not talking to you,' then you have to subpoena him, and now we're in a fight. So the question is, how badly does Mueller want that interview?"

Trump is a significant witness in the collusion thread of the Russia probe, but he is arguably the most important witness to Mueller's obstruction-of-justice case. The FBI began investigating the president for obstruction after he fired then FBI Director James Comey last year and later said on national television that he ousted Comey because he was displeased with the Russia investigation.

"The written answers from the president, which are really answers from his attorneys, are absolutely useless to Mueller," Cramer said. "Trump's lawyers can scrub that document. But in a one-on-one interview, anyone can lie for the first one or two layers of questions. It's when you start going deeper that things start to unravel."

If Mueller decided to subpoena Trump, it wouldn't be the first time a sitting president has been at the receiving end of the move. Former presidents Thomas Jefferson, Richard Nixon, and Bill Clinton were all subpoenaed while in office.

For now, legal experts expect the special counsel to stay mum for at least the next week or two.

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