Update: On Tuesday, emails between Donald Trump Jr. and a man claiming to have information from the Russian government were released. An expert told The Post’s Amber Phillips that the interaction might very well suggest that Trump Jr. had committed a crime.

In light of that, we’re re-publishing this story looking at the breadth of Trump’s ability to issue pardons as president, originally written in April when former national security adviser Michael Flynn was under scrutiny for his conversations with the ambassador from Russia.

In short? Trump can certainly pardon Flynn or his son, even before charges have been filed.

Given that it is a weekday during the year 2017, there are new revelations about the extent to which former national security adviser Michael Flynn may have violated federal rules at some point prior to being appointed to the administration of President Trump.

This time, members of the House Oversight Committee announced that the Pentagon’s inspector general would look into whether Flynn failed to get the necessary clearance for accepting payments from a foreign government, which he did when appearing at an event for the Russia-backed television network RT. Previously, questions have been raised about conversations Flynn had with the Russian ambassador during the period between the election and the inauguration.

We’ve reached the point where it’s worth asking a perhaps inevitable question: Can Trump pardon Flynn? And, if so, when can he do it?

To answer those questions, I spoke with P.S. Ruckman, a professor at Rock Valley College who tracks presidential pardons at his blog Pardon Power. The answers, in short: Trump can certainly pardon Flynn, and he can do it whenever he wants.

“The conventional wisdom or the Supreme Court jargon to-date suggests that a president can pardon someone before, during or after conviction,” Ruckman said. “Is it possible Trump could pardon for crimes he may have committed in some period of time? Absolutely, yes.”

Ruckman points to the example of President Gerald Ford who, soon after taking office, pardoned his predecessor Richard Nixon for any crimes Nixon may have committed. This is the most well-known example of a blanket pardon, but it’s hardly the only one. “I wouldn’t call it common” for such pardons to be granted, Ruckman said, “but it’s kind of like finding a dollar on the sidewalk: You don’t call The Post to report that.” He notes that as early as 1821, James Monroe issued such a pardon.

The power of presidential pardon is exceptionally broad. Could Trump pardon everyone in America for crimes they may have committed over a period of time? Yes, Ruckman says — with the caveat that the crimes would have to be federal crimes or crimes committed in the District of Columbia. (He explained that, in the early days of the presidency, pardons for local D.C. crimes actually happened, including, according to his data, a pardon for chicken theft in the district.)

The checks on such a move are fairly limited: Trump could be impeached and removed from office and those pardons could be revoked by the president who replaced him. Such revocations are rare but not impossible. George W. Bush revoked his own pardon of a man named Isaac Toussie in 2008, after learning that Toussie’s father had contributed to Republican politicians. (The pardon could be revoked because it hadn’t yet reached Toussie.)

Of course, such a move would also be a dramatic breach with precedent. A high-profile blanket pardon so early in a presidency would be highly unusual, Ruckman noted. He detailed a handful of pardons early in presidencies that were high-profile, including that pardon of Nixon and Ronald Reagan’s pardons of two FBI agents — including the man we later learned was Watergate’s Deep Throat — for illegal searches in the early 1970s.

A pardon before charges were filed in a high-profile case would be similarly unusual. When Scooter Libby, an aide to former vice president Richard B. Cheney, came under suspicion during Bush’s presidency, there were calls to issue a preemptive pardon that Bush declined to entertain. (He did subsequently commute Libby’s sentence.)

Were Trump to pardon Flynn at this point, it would also be a breach of guidelines set by the Department of Justice, which sets timelines and procedures that Trump would be sidestepping. Not to mention the political cost. Should Trump pardon Flynn, it would immediately increase the amount of attention paid to Flynn’s ties to Russia and raise strong questions about Trump’s desire to avoid having those ties adjudicated in public.

Put another way, most presidents would avoid the move, for all of these reasons. But Trump isn’t most presidents.

“You can’t toss aside the fact that he is so unpredictable and willing to do things that are outside the norm, and for whatever reason,” Ruckman said. “You get the feeling that he’s a person who would act outside the norms without feeling the necessity to have an elaborate spelled out explanation. He’s more the Andrew Jackson, I’ll-just-do-it-because-I-want-to.”

Trump, for example, has repeatedly expressed his frustration with the courts. If a loyal aide faced a trial before a judge, it certainly would fit with Trump’s past behavior for him to airlift Flynn out of the process. Remember his reaction when Flynn was considering seeking immunity in order to testify before the Senate:

At any point in time, Trump could extricate Flynn from any perceived judicial witch hunt, granting him immunity for any federal crimes. There would be political fallout. But that it would be so unusual may be as much of a reason for Trump to do it as anything.