Last Friday, special counsel Robert Mueller’s team indicted 13 Russian citizens and three Russian companies, accusing them of conspiring to interfere with the 2016 presidential election and help Donald Trump win the White House.

It’s hard to know what this means given how wide and complex the Mueller probe has become. As my Vox colleague Jennifer Williams noted, the latest charges have tremendous new detail about how actively the Russians tried to meddle with the elections but don’t directly implicate anyone in the Trump campaign or in his inner circle.

But they do raise a few legal questions.

First, do the indictments signal where the broader investigation into Trump-Russia collusion might be headed? Second, although the indictment says clearly that Trump’s people “unwittingly” got help from Russians, does that mean that they’re legally protected from prosecution? And finally, in the unlikely event that any of these Russian citizens are indicted, how difficult will it be to prove that they conspired to defraud the United States?

To answers these questions, I reached out to 7 legal experts. Their responses, lightly edited for clarity and style, are below.

Diane Marie Amann, law professor, University of Georgia

The allegations in the indictment against the Russian citizens and companies support many prior news reports about the extent and sophistication of interference in the 2016 election. But that may not be the most significant aspect of Friday’s news.

Especially intriguing are these words: “and their co-conspirators.” The words are repeated in all counts, in reference after reference to the named defendants. That repetition signals that this indictment presents only half a picture. Yet to come is the mirror image — the identification of and charges against co-conspirators.

Like the already-named defendants, those co-conspirators will be charged with knowledge of alleged crimes, unlike the “unwitting” persons whom this indictment says they exploited. And while resistance to international extradition may shield indicted Russians from US prosecution, it seems likely that some of the alleged co-conspirators will be Americans, fully subject to trial in the United States.

“The indictment does make it much more difficult for Trump to fire Mueller or Rosenstein without risking another nail in any ‘obstruction of justice’ charge”

Miriam Baer, law professor, Brooklyn Law School

There are two types of conspiracies a prosecutor can charge. The more common one occurs when two or more individuals have conspired to violate some other crime, such as computer fraud, or bribery, or some other offense.

The less common usage, which is the one we see in Robert Mueller’s latest indictment, is the so-called “conspiracy to defraud the United States.” For this kind of conspiracy, the government must show that the conspirators agreed to interfere with one of the federal government’s lawful “functions.”

The theory underlying Mueller’s indictment is that the conspirators agreed to obstruct the federal government’s “lawful function” of administering its own election laws. Although prosecutions such as these are relatively rare, they are not unprecedented.

As for the American individuals who may have “unwittingly” helped the conspirators, they have nothing to worry about, at least in regard to this indictment. One cannot unwittingly join a conspiracy; the core of conspiracy is the existence of an agreement to violate the law.

Then again, as others have already pointed out, this indictment describes only one conspiracy. It says nothing about other conspiracies (e.g., conspiracies to hack computers). Nor does it foreclose the filing of a superseding indictment, naming either more crimes or more defendants, should the grand jury become aware of additional individuals who aided in Russia’s disinformation campaign.

Ric Simmons, law professor, Ohio State University

These indictments say nothing about intentional collusion between the Trump campaign and Russian interference in the election. They do not implicate nor exonerate anyone in the Trump campaign. They merely allege that Russian nationals interfered with the 2016 presidential election, a fact that was already well known.

The Russian nationals who are named in the indictments are unlikely to ever face trial in the United States, but if they did, it appears from the indictments that the special counsel has ample evidence to convict them of the conspiracy charges. To win a conspiracy case, a prosecutor need only prove that the defendants agreed to commit an illegal act and took at least one overt act to further that agreement. The indictments detail multiple agreements to defraud the United States and commit wire fraud and bank fraud, and multiple overt acts to further those plans.

Regarding any Americans referenced in this particular charging document, ignorance would be a complete defense for the Trump campaign workers who unwittingly got help from Russian agents. But the indictments only describe interactions between Russian agents and relatively low-level campaign workers.

These low-level workers are not charged in the indictments, and they are unlikely to ever be charged. The indictments simply do not address the question of whether anyone in the highest levels of the Trump campaign knowingly worked with the Russian agents to interfere with the election. To learn what (if anything) the special counsel will allege regarding such collusion, we will simply have to wait.

“This indictment presents only half a picture”

Jed Shugerman, law professor, Fordham University

The basic facts alleged in the indictments of 13 Russians were not surprising to those following the news of Russian manipulation of Facebook and Twitter, but I was surprised by the details of identity theft and bank fraud. Those specific crimes are more concrete and more easily proven than violations of campaign finance law or election law, and that puts anyone who conspired with them in more serious legal jeopardy.

These indictments do mention “unwitting” Americans, which appears to let the Trump campaign off the hook. But I’d note three things here:

1. This is a more careful and professional way for Mueller to phrase an indictment at this point.

2. Mueller has good reasons to avoid politically contentious allegations now, considering how polarized the environment is.

3. Mueller unsealed a guilty plea by a “witting” American co-conspirator on the same day, showing that there is more behind this indictment of Russians than innocent mistake.

Even if the indictment avoids specifying that any Trump campaign officials knowingly conspired, that doesn’t mean Mueller already has evidence of it or is on his way to finding it. Mueller likely has evidence to turn collusion into a conspiracy charge, and he’s using this approach in his indictments.

Joshua Dressler, law professor, Ohio State University

I don’t think the indictments do more than demonstrate what everyone (except, it seems, the president) has realized for a long time — namely, that there was Russian interference in our election for the purpose of helping Trump to be elected. It also shows that people close to Trump may have assisted in that process.

However, to the extent that it was unwitting, that likely protects them from prosecution for their assistance to the Russians. Of course, the investigations are not over yet, so we still remain uncertain regarding the extent of potential criminality.

What remains so interesting to me is a separate question: Why did the Russians so desperately want to elect Trump? They obviously wanted him from the very start, as we now know they worked to help him get the nomination by harming [Ted] Cruz and [Marco] Rubio.

Susan Bloch, law professor, Georgetown University

Mueller’s indictment of the 13 Russians makes it hard to deny Russian involvement in our election. But President Trump and his family will still deny collusion. To be found guilty of collusion or conspiracy to interfere with our election does require “knowledge” and “intent,” so the term “unwittingly” in the indictment does help the Trump family’s defense.

At the same time, the indictment does make it much more difficult for Trump to fire Mueller or [Deputy Attorney General Rod] Rosenstein without risking another nail in any “obstruction of justice” charge. That may be the strongest motive behind Mueller’s announcing the indictment at this time.

Jessica Levinson, law professor, Loyola Law School

We know that Special Counsel Robert Mueller’s investigation is not a witch-hunt or a hoax. We, once again, have proof that at least one side of a potential conspiracy — the Russian side — tried to sway the 2016 presidential election.

I read the indictment as indicating that Mueller has not yet come forward with evidence that President Trump’s campaign or administration attempted to aid Russian nationals. That evidence may never materialize, but the indictment does not close the door on this issue.