Americans have puzzling and often contradictory beliefs about the US legal system. While most Americans trust their courts, lawyers rank just above used car salesmen in public disdain; lawyers are even less admired than journalists, who aren't admired at all.

Nurses, doctors, pharmacists and engineers, for some reason, top the list of the United States' most trusted professions, while the least trusted are members of Congress. That is, the government of laws that Americans admire are written by those who Americans don't.

A further befuddling corollary to this is that while the vast majority of Americans reserve their greatest mistrust for members of the US Congress - fully 59 percent have a "low" or "very low" opinion of them, according to a recent poll - they find it intolerable when someone lies to them.

Take the case of Elliott Abrams. An experienced US diplomat and Washington insider, Abrams was, until recently, in the running for the No 2 job at Rex Tillerson's State Department.

Articulate, hardworking and experienced, Abrams got caught up in the Iran-contra scandal of the 1980s, and lied about his role in it. He pleaded guilty to two counts of "withholding information from the Congress", and while he was later pardoned - by George HW Bush - his name cannot now appear in print without being followed by a two word descriptive: "convicted liar".

Of course, Abrams admission of "withholding information" isn't what nixed his nomination to the State Department's No 2 spot, it was President Donald Trump's discovery that Abrams had criticised him during the campaign, a far greater sin, presumably, than public mendacity. That said, if it wasn't axiomatic before, it is now: the American people don't respect the Congress, but you better not lie to them.

Abrams syndrome

That's the problem now being faced by Jeff Sessions, the former federal judge and US Senator who Trump appointed as his attorney general - the nation's chief law enforcement officer.

At issue is testimony Sessions gave back in January, during his confirmation hearings, before the Senate Judiciary Committee - which is stocked with lawyers. When asked by them whether he'd had any contact with Russian officials when Trump was running for president, he said he hadn't. His denial was authoritative: "I did not have communications with the Russians," he said.

In fact, he did. According to published reports, Sessions met the Russian ambassador to the US Sergey Kislyak just as Trump was accepting the nomination of his party during their convention in Cleveland.

Additionally, according to the Washington Post, Sessions met Kislyak in his Senate office at the end of September, as Trump was campaigning for the presidency.

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While it is not known what Sessions and Kislyak talked about, the report stunned the Congress - not least because of allegations that the Vladimir Putin government was engaged in a covert programme to influence the outcome of the US election in favour of Trump.

Put simply, Sessions has an Abrams problem: the issue is not that he talked to a Russian official - that's not against the law, at least not yet - but that he lied about it. The former claim can put a chink in your political credibility, the latter claim can land you in jail.

Sessions attempted to dampen the firestorm that greeted these reports by saying that, while he had met Kislyak, their meetings had nothing to do with the Trump campaign.

"I never met with any Russian officials to discuss issues of the campaign," Sessions announced in a statement. "I have no idea what this allegation is about. It is false."

The newly minted president can either tell everything about his - and his aides - contacts with Russian officials or he can order his administration to continue the delicate and dangerous dance of shaving the truth.

In effect, however, the Sessions statement highlighted his Abrams' problem: he hadn't exactly lied, he claimed, but there wasn't much doubt that he had withheld information - which is what got Abrams disbarred and is, though arguably, a violation of the law that he was confirmed to enforce.

Then too, the Sessions statement begged any number of embarrassing questions, such as: if President Trump's former national security adviser, Michael Flynn, was forced out of his job for lying about the same thing to the vice president, why wasn't Trump insisting that Sessions resign for lying about it to the Congress?

Predictably, Democratic Party opponents of Trump called for an investigation to determine whether Sessions had lied, while Trump's Republican supporters - there are fewer of them every day - immediately called on Sessions to "recuse" himself in any investigation of the burgeoning scandal. Sessions has since done so, in an announcement made by the Justice Department as this article went to press.

So now what?

In this case, at least, the past provides a useful model. The history of US political scandals shows that, while the American public is notoriously forgiving of political double-dealing - and have even, in some sense, come to expect it - they are intolerant of those who attempt to cover it up.

This was true even in the midst of the nation's gravest political scandal, when a team of Nixon administration operatives broke into the headquarters of the Democratic Party at the Watergate, a complex of offices and residences, back in 1972.

If Nixon had admitted that the White House had ordered the break in, and it was a terrible mistake, the subsequent investigation that unravelled his presidency might have gone no further.

Instead, Nixon ordered that information about the break-in to be suppressed, which led to further investigations, which led to further cover-ups and more investigations, a major constitutional crisis - and Nixon's humiliating resignation from office. While it's hard to imagine now, it could have been otherwise.

So too, in the 1980s, after the Ronald Reagan administration used the proceeds of arms shipments to Iran to fund the anti-communist Nicaraguan "contras" - in violation of the law - the White House took steps to protect administration officials from prosecution, including destroying public documents about the operation and lying about it to the Congress, a felony.

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The resulting public hearings gravely wounded the Reagan presidency, eroded Reagan's credibility and led to the indictment of nearly a dozen administration officials.

It didn't need to happen: if Reagan, who was enormously popular, had gone before the American people and admitted to a mistake, the scandal would have been relegated to the status of an embarrassing political error - but little more.

At a key point in both cases, those in the White House made a choice between telling the truth, or covering up the facts in the hope that the scandal would burn itself out.

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That's where the US is now. The Jeff Sessions lie to the Senate about his meetings with Russian officials has brought the Trump administration to a crossroads: the newly minted president can either tell everything about his, and his aides, contacts with Russian officials, or he can order his administration to continue the delicate and dangerous dance of shaving the truth.

The difference between the two, particularly for those skeptics who believe the reporting about Russia's influence on the election is thin, and politically motivated, might well be the difference between a tempest in a teapot - and a political volcano.

Mark Perry is a Washington, DC-based foreign policy analyst, reporter and the author of nine books on US political and military history.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.