It’s only six months into Donald Trump’s presidency — and he’s already looking into his powers to pardon his top aides and family members for unspecified crimes, according to a report from the Washington Post published Thursday night.

One source told the paper that presidential pardon powers were under discussion among Trump’s lawyers. But another source went further, telling the Post that “Trump has asked his advisers about his power to pardon aides, family members and even himself in connection with the probe.” And a Trump adviser seemingly confirmed the report to the paper, saying that the president was simply curious.

Jay Sekulow, a lawyer for Trump, told CBS News Friday morning that “[p]ardons are not being discussed and are not on the table.” But if this report is true, Trump is apparently worried enough about his, his family members’ and his top aides’ legal exposure in special counsel Robert Mueller’s Russia investigation that he’s already looking into pardons before anyone’s been convicted or even charged with any crimes.

To be clear: It would be utterly shocking, and seemingly without any real precedent in US history, for a sitting president to pardon close aides or family members facing investigation.

And it would also seemingly be within the president’s powers. The pardon power is incredibly wide-ranging. A president can pardon essentially all federal crimes at any point after they’ve been committed — even if they haven’t yet been charged or convicted.

What’s prevented past presidents, including Richard Nixon at the height of Watergate, from doing something like this has been the fear of political backlash. And that may yet restrain Trump too — this, for the moment, seems to fall into the category of brainstorming rather than concrete planning.

But of course, Trump has frequently proven himself willing to flout the norms and traditions of American politics with glee, regardless of the backlash that may ensue. And he may yet do so again, calculating that his voters will stick with him regardless.

If he does, he’d set up the US constitutional system for its biggest test since Watergate — and the question would be whether the Republican Party would bother to do anything about it.

No past president has done anything like this

Past presidents have, of course, used the pardon power in controversial ways — but in ways that have fallen far short of what Trump is reportedly musing about.

Instead, the most controversial uses of the pardon power have generally come from presidents pardoning crimes committed by their political allies under their predecessors’ administrations, or from lame-duck presidents already headed out the door.

For instance:

President Gerald Ford gave Richard Nixon an unconditional pardon for any federal crimes committed while president of the United States, but that was only after Nixon resigned the presidency due to the Watergate scandal.

President George H.W. Bush pardoned several officials who served in his predecessor Ronald Reagan’s administration and were set to stand trial for charges related to the Iran-Contra scandal — but only after he had lost reelection and was in his lame-duck period in late 1992.

President Bill Clinton pardoned major Democratic donor Marc Rich, who had fled the country decades ago rather than face charges on tax evasion and other matters. (He also pardoned his half-brother Roger Clinton, but this was for a crime he had already served out his sentence for, so the pardon was to expunge a record rather than evade justice.)

All of these proved to be controversial. Yet none of them involved pardons to short-circuit a major scandal in the current administration that was still being investigated.

Nixon didn’t do this during Watergate, Reagan didn’t do this during Iran-Contra, Clinton didn’t do this during the Starr investigations, and George W. Bush didn’t do this during the US attorney firing scandal or Plamegate (though he did commute a prison sentence for his aide Scooter Libby after Libby was convicted of perjury and obstruction of justice in connection with that investigation).

Trump keeps defying norms

But as with so much in American politics, past presidents haven’t aggressively used the pardon power to protect themselves and their close aides from ongoing investigations because of norms rather than concrete rules.

Norms have restrained presidents from doing anything like this because, well, no one else has, and it sure would seem to be beyond the pale of American politics. It’s much more common for presidents to profess respect for the rule of law and to avow that they hope investigators get to the bottom of whether any crimes were committed.

Norms have also indirectly constrained past presidents from abusing the pardon power so boldly, due to fear of political backlash. They’ve calculated that if they violated this norm, they’d face enormous condemnation from the political system, including from their own party.

But of course Donald Trump has gleefully defied norm after norm in American politics already, and repeatedly chosen to do the things he’s been told or warned that he simply “can’t” or shouldn’t do.

From denouncing unauthorized immigrants as criminals and rapists to proposing to ban all Muslims from the United States to refusing to release his tax returns to insulting ordinary citizens to retaining ownership of his businesses after being sworn in to repeatedly tweeting unvetted or false statements, like the accusation that Barack Obama tapped his phones, to firing the FBI director investigating his campaign, Trump has gone far beyond what’s been considered acceptable in our politics — and he keeps getting away with it.

It will all be up to congressional Republicans

Considering how Trump has operated so far, the main constraint that seems to be preventing him from going even further — whether by issuing preemptive pardons or, perhaps more realistically in the near term, firing special counsel Robert Mueller and top Justice Department officials — is likely just fear that such actions would cause a massive backlash and end up being counterproductive.

But it’s genuinely unclear whether this backlash would in fact materialize among the people who really matter: Republicans in control of Congress.

Partly in fear of angering their own voters, and partly because they hope to win policy victories in a rare moment of unified control of Washington, Republicans have often averted their eyes from Trump’s most controversial actions, rather than criticizing him for them.

Occasionally — such as after the firing of FBI Director James Comey — various Republicans will release various statements expressing disagreement or disappointment with the president’s action. Yet afterward they all seem to simply move on, so some observers think they will do the same for any future controversial action. “Trump fired Comey. There was some tumult. But life went on. So it will be if/when Trump fires Mueller,” Jay Nordlinger of National Review tweeted.

After all, there will always be some pretext or talking point that can be used by the president’s supporters to justify him. Fox News and other conservative media outlets will be willing to defend him. And even in the lowest moments of the Watergate scandal, about a quarter of the country remained supportive of Nixon. So, some conclude, there is really nothing stopping Trump from doing whatever he wants — partisanship will triumph over all.

Yet in an insightful piece at the Atlantic, McKay Coppins spoke to several Republicans on Capitol Hill about this on background, and found that they insisted and seemed to believe they were investigating Trump to the extent reasonable. “All of them believe they’re already doing everything they can within reason to hold the president accountable — and they fiercely reject any argument to the contrary,” Coppins wrote.

As suspicious as many of Trump and his advisers’ actions around the Russia scandal may seem, there remains no actual proof there was any significant collusion between his team and Russia. That’s what the investigations are meant to find out.

Furthermore, the political backlash (including among many Republicans) after the Comey firing and subsequent revelations did lead to the appointment of Mueller as special counsel.

Beyond Mueller, various congressional committees led by Republicans are investigating Russian interference. For instance, the Senate Intelligence Committee is running what appears to be a serious and substantive investigation, and the Senate Judiciary Committee is now asking Paul Manafort and Donald Trump Jr. to testify before them and threatening subpoenas.

So there is a line of thinking in Washington that Republicans are already looking into Trump rather than letting him get off scot-free — and that if Trump did anything really extreme, like firing Mueller or preemptively pardoning his aides, that would be a bridge too far.

Maybe. And yet in the past year you’d never have gone broke betting on the willingness of the Republican Party to fold to Donald Trump.