Newark, New Jersey (CNN) Sen. Bob Menendez's federal corruption trial is expected to last several more weeks, but a cryptic comment from the judge presiding over the case has renewed questions about whether it will even go to the jury.

"I am very careful because of you know what and that being McDonnell," Judge William Walls said last week -- issuing the legal equivalent of a thunderclap in the courtroom.

The trial will resume Tuesday for its sixth week, although court has only been in session 16 days thus far.

The "McDonnell" bomb that Walls dropped is a 2016 Supreme Court case unanimously tossing out the bribery conviction of former Virginia GOP Gov. Bob McDonnell -- a result that has produced a gold mine of litigation for defense attorneys seeking to upend guilty verdicts in corruption cases.

A slew of former governmental officials from both parties -- including Democrats Louisiana Rep. William Jefferson , New York state Assembly Speaker Sheldon Silver , and Republican New York state Senate Majority Leader Dean Skelos -- have all benefited from the McDonnell fallout with recently overturned convictions.

Defense attorneys for Menendez, a New Jersey Democrat, tried to get the senator's case thrown out before trial using McDonnell, but Walls deferred ruling on the motion at that time, saying he needed to see how the evidence at trial played out.

Now, in a trial that could last past Thanksgiving, the judge's musings prove as a reminder of the high burden prosecutors must reach to prove their case.

"Official acts"

The heart of the Justice Department's case rests on a theory that Menendez accepted political contributions, free rides on private jets and a swanky hotel suite in Paris from a wealthy doctor from Florida, Dr. Salomon Melgen. In exchange, they argue, the senator agreed to use the power of his office to encourage other high-level federal officials in the executive branch to help resolve Melgen's business problems -- "official acts" prosecutors claim put Menendez on the hook under federal bribery law.

Menendez and Melgen deny the charges.

The challenge for prosecutors is that the Supreme Court in McDonnell narrowed the types of "official acts" that can form the basis of the crime.

The justices said that merely "setting up a meeting, hosting an event, or calling an official" is no longer sufficient -- the politician must put his or her thumb on the scale in an ongoing proceeding, lawsuit or controversy, or "exert pressure" on someone else to do so.

"You need evidence from which a jury could reasonably infer that (Menendez) was seeking an official act," said Fordham Law School Professor Zephyr Teachout, a former Democratic congressional candidate who teaches classes on corruption laws.

"That does not mean that you need anybody in particular to say 'I knew that he was seeking x or y official act' -- it can include circumstantial evidence," she added.

Prosecutors specifically accuse Menendez of pushing officials to make national health care policy changes that would have resulted in a favorable outcome in Melgen's multimillion-dollar dispute with the Centers for Medicare and Medicaid Services. The indictment also alleges the senator encouraged State Department officials to intercede in a contract dispute Melgen had with the government of the Dominican Republic for cargo screening at the island's ports.

To prove its case, prosecutors have introduced stacks of emails, flight records, customs forms, credit card receipts, invoices and glitzy hotel brochures. They have called 35 witnesses to the stand thus far, including FBI agents, pilots, former Democratic Sen. Tom Harkin, former Health and Human Services Secretary Kathleen Sebelius, former US ambassador to Guatemala Todd Robinson, and a bevy of former congressional staffers.

One witness not expected to be called: former Senate Majority Leader Harry Reid, who was part of a meeting on the Medicare rules with Menendez and Sebelius.

'The elephant in the room'

The defense team doesn't deny gifts changed hands between the two longtime friends Menendez and Melgen, but instead says no legal wrongdoing occurred, in large part because the senator -- who lawyers remind the jury had no power to resolve Melgen's business disputes as a legislator -- had broader policy concerns in mind when he contacted officials within the executive branch.

Melgen faced an $8.9 million repayment demand from CMS over his billing practice for the eye drug Lucentis and prosecutors accuse Menendez of lobbying various officials to make the case go away.

But defense lawyers have frequently elicited testimony suggesting Menendez wasn't a particularly successful advocate -- as witnesses have uniformly stated that they either never agreed to help Melgen, despite repeated entreaties from Menendez and his staff, or others say they simply couldn't pin down his precise "ask."

"I don't exactly know what he wanted other than for me to do something," Sebelius told jurors about a 2012 meeting she attended with Menendez and Reid.

"There was confusion about what they were asking our office to do and I wasn't clear on that," added a former Reid aide when asked if Menendez wanted officials to "interfere" in Melgen's case.

Multiple witnesses have also told jurors Menendez's concern -- at least expressed to them -- was that he viewed CMS' billing practices as unfair and resulting in a windfall for drug companies -- never referencing his friend or Lucentis directly.

Defense lawyers, and now Judge Walls, have pounced on this fact.

"(N)o bureaucrat who has testified here so far within my hearing has indicated that this particular Senator raised the name of his alleged friend in the meetings," Walls said. "I have been very careful to listen to that. Because in the teachings of McDonnell, we are really thinking about things."

But several legal experts interviewed by CNN were skeptical the McDonnell decision means Menendez had to reference Melgen explicitly by name in order for the senator's advocacy on behalf of his friend to constitute an "official act."

"Menendez doesn't have to because it's the elephant in the room," said Michael Weinstein, a former trial attorney at DOJ and now at Cole Schotz law firm in New Jersey. "Through inference, innuendo and flexing his senatorial muscle, he gets people to be in a room that would never have been in the first place."