A source close to former Trump strategist Stephen K. Bannon tells NBC News that Bannon will answer “any questions” that special counsel Robert S. Mueller III wants to ask. Or, as a Bannon source put it to the Daily Beast, Mueller “will hear everything Bannon has to say.”

Bannon, of course, made national news when Michael Wolff’s book quoted him describing Donald Trump Jr.’s meeting with a Russian lawyer as “treasonous.” But Mueller, who has subpoenaed Bannon to appear before a grand jury, is not going to be interested in Bannon’s opinion. He’s going to be interested in information. And chances are that Bannon is in possession of a fair amount of it.

Here’s a partial rundown of what Mueller will want to know:

Did President Trump tell Flynn to lie to the FBI? Mueller is reportedly trying to reconstruct what happened during the transition, when former national security adviser Michael Flynn lied to the FBI about his transition contacts with the Russian ambassador, to which Flynn has pleaded guilty. Susan Hennessey, a legal analyst for the Lawfare blog, tells me Mueller will want to know: “Did the president instruct Flynn to lie to the FBI?”

What does Bannon know about Trump’s firing of Comey? Former FBI director James B. Comey has testified that once in office, Trump demanded his “loyalty” and pressed him to drop the probe (“let this go”) into Flynn. As Hennessey points out, whether Trump did or didn’t instruct Flynn to lie to the FBI, Mueller will ask Bannon “if the president was aware Flynn had lied to the FBI” before pushing Comey to “let this go.” Depending on the answers, either of these two lines of inquiry could strengthen the case that obstruction of justice took place.

What does Bannon know about the Trump Tower meeting and its aftermath? Bannon was not present at the June 2016 meeting that Trump Jr. held with a Russian lawyer to get info on Hillary Clinton furnished by the Russian government. But Paul Rosenzweig, a senior counsel on Ken Starr’s investigation into Bill Clinton, tells me: “Mueller wants to know what facts Bannon learned about the meeting, from whom he learned them, and when he learned them.”

Opinion | If President Trump fires the bane of his legal troubles, he could spark a legal and constitutional crisis. (Adriana Usero/The Washington Post)

Mueller is trying to flesh out the full set of facts about “whether representatives of the Trump campaign knowingly solicited dirt on Hillary Clinton from agents of the Russian government,” Rosenzweig adds. Trump Jr.’s emails at the time already show he did do this, but Rosenzweig notes that Mueller will ask Bannon whether there was any follow-up or expectation (or outright provision) of future dirt.

And so, Rosenzweig says, Mueller will press Bannon to detail any internal communications about that meeting, including: “Did you ever talk about that meeting with Donald Trump?” Meaning President Trump.

What did George Papadopoulos communicate to campaign higher-ups? Trump adviser George Papadopoulos has admitted in his plea deal that he had been informed that the Russian government had dirt on Clinton, but it’s unknown whether Papadopoulos communicated this to senior campaign officials. Mueller may ask Bannon to shed light on that question, Rosenzweig notes, adding that Mueller will also ask Bannon to detail any possible Russia-Trump campaign conspiracy that we — meaning you and I, not Mueller — don’t know about yet.

“This is an interesting dance, because Bannon doesn’t know what Mueller knows,” Rosenzweig says.

What about Bannon’s money-laundering comments? Bannon also told Michael Wolff that Mueller’s probe is “all about money laundering,” hinting that Trump Jr. and Jared Kushner are somehow implicated. Hennessey tells me that Mueller, like any prosecutor, will “want to know if that’s just Bannon speculating the way any person on the street might be, or whether he has some real underlying knowledge of criminal behavior.”

What about internal campaign atmospherics? Former federal prosecutor Renato Mariotti tells me that Mueller may ask Bannon to explain the internal workings of the campaign in a general sense, in particular “how individuals interacted with each other.” For instance, Mariotti notes, Mueller’s questioning could theoretically lead Bannon to say: “I don’t remember a day that went by when Trump Jr. didn’t download everything to Trump.” This could shed more light on what Trump Jr. might have conveyed to his father about knowledge of “Russian efforts to aid the Trump campaign,” Mariotti notes.

In the end, we just don’t know what Bannon knows or is willing to say. But as Hennessey points out: “It’s not obvious the extent to which Bannon is in a position to answer any of that, but he was certainly in the inner circle at the relevant time and Mueller is certainly going to want to hear what he knows.” Which means Trump may come to regret his falling-out with Bannon soon enough.

* AMERICANS WANT MUELLER TO CARRY OUT PROBE: A new PBS-NPR-Marist poll finds that Americans say, 68 percent to 14 percent, that Mueller should be allowed to finish his investigation. Even Republicans say this, by 59-23.

Meanwhile, Americans also say the probe has been fair by 48-28, and 57 percent have quite a lot (33) or a great deal (24) of confidence in the FBI. That campaign to delegitimize efforts to hold Trump accountable is going great!

* WILL SENATE DEMOCRATS STAND FIRM? Republicans are set to push a short-term spending bill paired with funding for CHIP, but no solution for the “dreamers,” and dare Democrats to vote no and provoke a shutdown. The New York Times reports:

If Republican leaders can push the bill through the House this week, the Senate — where at least nine Democratic votes will be needed — is no sure bet. Some Democrats in that chamber … are expected to oppose any spending measure that does not protect the young undocumented immigrants. But Democrats up for re-election this year may be reluctant to oppose the bill and risk being blamed for a shutdown.

Presumably those vulnerable Democrats in Trump states could vote for the bill while the rest of Senate Democrats stand firm for the dreamers, even if it does result in a shutdown.

The 16 Democrats … could be a good starting point to predict the outcome this week. After they voted for the bill, many of them — some who are facing tough re-election campaigns this year — were hammered by immigration advocates and the Democratic base for doing just that.

CNN lists them all here. One imagines the attacks on them from the left will be even harsher if they fold this time.

* MORE SIGNS OF A DEMOCRATIC WAVE? Last night, Democrat Patty Schachtner flipped a State Senate seat in rural Wisconsin from red to blue, winning it by nine points. This is a district that a Republican won in 2016 by 26 points and that Trump won by 17 points.

Wisconsin Gov. Scott Walker tweeted that the outcome “was a wake-up call for Republicans in Wisconsin.” And, perhaps, across the country.

While many Republicans insist the Trump-Russia saga is overblown, they worry headlines about federal indictments, high profile trials — and a potential blockbuster meeting between Mueller and Trump himself — could obscure their positive message ahead of November elections and threaten their House and Senate majorities.

And as one GOP strategist tells Politico, Paul Manafort’s trial is set to start this fall, just as early voting is underway.

* JEFF FLAKE SET TO GIVE ANTI-TRUMP SPEECH: Sen. Jeff Flake (R-Ariz.) is set to give a big speech on the Senate floor today about Trump’s degradation of our politics and democracy.

There will be a lot of chortling from liberals today about how Flake votes with Trump 99.9999 percent o of the time. That’s true, but there’s still some value in having Republicans criticize Trump, particularly if they cast him as unfit to serve (something we should be watching for).