When the first indictments against President Donald Trump’s aides were made public on Monday, the White House and its allies crowed. No biggie, they argued: the charges aimed at former campaign chairman Paul Manafort and his erstwhile business partner Rick Gates don’t involve anything that happened during the 2016 campaign. They didn’t even tie together Team Trump and the Kremlin, at least not directly.

Instead, Mueller’s investigators dug into the not-too-distant past, dredging up allegations of tax evasion, money laundering, and lobbying done in secret.

“NO COLLUSION!” the president tweeted.

But seasoned observers quickly saw that the charges were more ominous for the White House than they at first appeared. The Manafort and Gates indictments made clear that Mueller is perfectly comfortable bringing charges related to activity that happened years before Trump took his historic escalator ride.

For special counsel Robert Mueller and his team of seasoned federal prosecutors, not much is off limits. And that could spell all kinds of trouble for a president who has sought to keep his finances private, surrounded by top aides who have all kinds of interesting financial entanglements of their own.

Mueller “certainly is acting as if, in fact, he has jurisdiction to investigate any and all offenses in the statute of limitations, of all the people who he is investigating in the first place,” said David Rivkin, an attorney who formerly worked in the George H. W. Bush and Reagan administrations.

In other words, if someone in Trump’s orbit committed a crime and the statute of limitations for that crime isn’t up—well, watch out.

The nature of any potential allegations could be nebulous. There has been widespread speculation that Michael Flynn, a retired general who had a short stint as Trump’s national security advisor, could have liability under the same foreign lobbying law that Manafort is charged with violating.

“For Flynn, the fact the Mueller was not afraid to charge the long-dormant FARA statute is really, really bad news,” a Justice Department official told The Daily Beast.

And if you ask any New York City real estate expert, they’ll tell you that anyone working in development there during the raucous 1980s and 1990s—including our current president—would start sweating if they knew someone like Mueller were scrutinizing their finances.

The president’s family members have also had their fair share of legal close calls, including reported legal jeopardy for Don Jr. and Ivanka over their efforts to sell condo units in Trump Tower SoHo. None of the president’s children have been indicted. And for the purposes of Mueller’s probe, they will all be considered campaign associates.

“The DOJ loves to bring money-laundering and bank fraud cases,” Rivkin added. “I find it surprising that this case was not brought several years earlier. What is it that is known now that made this case more compelling, from the DOJ’s perspective?”

When Deputy Attorney General Rod Rosenstein made Mueller the special counsel of the Russia probe on May 17 of this year, he gave him an extraordinarily broad mandate: to investigate “any links and/or coordination” between the Russian government and Trump campaign associates, and “any matters that arose or may arise” from that investigation.

The Monday indictments show what Mueller is willing to do with that mandate. Sol Wisenberg, a longtime Washington white-collar defense attorney, said it’s safe to expect Mueller to investigate any crime committed by a Trump campaign associate as long as the statute of limitations isn’t up and the crime could “shed light” on the probe’s broad focus.

“For example, if Trump himself was engaged in tax fraud and money laundering involving the Russians, that obviously could be relevant to whether or not he had a motive to facilitate any quote ‘collusion’ that may have happened,” Wisenberg added.

It is widely telegraphed that the White House’s most acute concerns about Mueller aren’t regarding potential collusion, but rather about all the other information his team could find in that process.

That’s not to say Mueller’s team didn’t find new examples of communication between Trump campaign associates and the Kremlin. Besides indicting Gates and Manafort, Team Mueller also revealed on Monday that George Papadopoulos—formerly a foreign policy advisor to the campaign—discussed “dirt” that Russian-linked individuals claimed to have on Hillary Clinton. None of Papadopoulos’s conversations broke the law, but he subsequently lied to the FBI about them. And that’s illegal.

The president has suggested in the past that he doesn’t want Mueller investigating his own personal finances. But as Mueller’s scrutiny of Manafort seems to make clear, he’s treating personal business dealings unrelated to campaign activity are fair game for his probe.

This may give his lawyers some anxiety. In August, Jay Sekulow—the spokesperson for the president’s legal team—told The New Yorker that the White House would consider a real estate deal that Trump made in the country of Georgia to be “out of scope” of the Mueller probe.

Given Monday’s indictments, it’s highly unlikely that Mueller would see things that way.

There’s chatter in some Washington conservative legal circles that defense lawyers for Mueller’s targets may argue in court that Rosenstein overstepped his bounds when he gave Mueller such a broad mandate. Prominent conservative legal voices have made this case already, including National Review columnist Andy McCarthy and Fox News legal analyst Greg Jarrett.

In a column published a few hours after the indictments came down, Jarrett argued that have given the targets’ lawyers a chance to shut down the probe for good.

“The indictments of Manafort and Gates now present a unique opportunity to challenge the authority of the special counsel,” he wrote. “Until now, no one had legal ‘standing’ to argue in court that the appointment of Mueller was illegal. The criminal charges change all that. The two defendants will be able to argue before a judge that Mueller’s appointment by Acting Attorney General Rod Rosenstein violated the special counsel law.”

Jarrett argued that the law which lets attorneys general appoint special counsels has limits, and that special counsels can only investigate crimes. He also pointed out that the order Rosenstein signed empowering Mueller directed him to investigate “matters that arose or may arise” from the probe—in other words, issues that may not be criminal.

“To put it plainly, Mueller is tasked with finding a crime that does not exist in the law,” Jarrett continued. “It is a legal impossibility. He is being asked to do something that is manifestly unattainable. If the federal judge agrees, Mueller and his team would be disbanded by judicial order.”

From Fox, Jarrett has an influential perch: He regularly appears on Hannity , which the president watches. And his columns are read widely by conservative lawyers.

McCarthy, meanwhile, made a similar argument at National Review on August 7.

“The regulation does not permit the Justice Department to appoint a special counsel in order to determine whether there is a basis for a criminal investigation,” he wrote. “To the contrary, the basis for a criminal investigation must pre-exist the appointment. It is the criminal investigation that triggers the special counsel, not the other way around. Rosenstein, instead, appointed a special counsel and unleashed him to sniff around and see if he could come up with a crime.”

It’s unclear what a court challenge of the scope of Mueller’s investigation could look like. But Mueller’s targets took a major hit on Monday. Don’t be surprised if they strike back.

—with reporting by Noah Shachtman