A senator meeting twice with the Russian ambassador is no political sin. Lying about it under sworn testimony? Well, so help you God.

Such is the furor that U.S. Attorney General Jeff Sessions now finds himself in. Calls for his resignation continue after a steady drumbeat pounded by both Republicans and Democrats.

Both parties urged him to recuse himself from overseeing investigations into the Trump campaign's ties to Russia. On Thursday, he announced he would step aside from the Trump-Russia probe.

But that recusal hasn't silenced demands for Sessions to quit as head of the Department of Justice. The uproar comes mostly from Democrats concerned about one fact: Sessions swore to tell the truth.

His opponents believe the Alabamian committed perjury when he testified with an unequivocal "No," when asked whether he spoke with anyone connected to the Russian government before or after election day.

Asked separately during a hearing about how he would deal with revelations that President Donald Trump's campaign might have ties with the Russian government, Sessions volunteered: "I didn't — did not — have communications with the Russians."

House of Representatives minority leader Nancy Pelosi speaks to reporters in Washington on Thursday about news reports of Sessions' contact with Russia's ambassador to the U.S. during the presidential campaign. (J. Scott Applewhite/Associated Press)

What Sessions did not disclose was that he did, in fact, speak twice with Russian ambassador Sergey Kislyak before the election, as the Washington Post revealed on Wednesday.

Sessions's denials in two answers were "at best, extremely misleading," Democratic Senator Al Franken said.

Even if the meetings were benign, their omission under sworn testimony revives transparency questions in a White House that has disregarded easily verifiable truths on everything from Trump's electoral vote tally to the Inauguration Day crowd size.

"The fact the attorney general, the top cop of our country, lied under oath to the American people is grounds for him to resign," Democratic minority House leader Nancy Pelosi said Thursday.

Protesters gather outside the Justice Department in Washington on Thursday during a demonstration against the attorney general. (Susan Walsh/Associated Press)

That was also enough for Democratic National Committee chairman Tom Perez.

"The rule of law is the rule of law," he told MSNBC.

Sessions played off his recusal from any investigation concerning the Trump campaign as a predetermined decision that had everything to do with his own conflict as a former campaign surrogate, not any of his meetings with Kislyak.

"At my confirmation hearing, I promised that I would do this," he reminded reporters.

Even so, constitutional lawyer Catherine Ross was troubled by the attorney general's apparent defiance. Sessions shrugged off the whole episode as an oversight, pledging to "write the judiciary committee soon" to amend the record.

Though Trump reiterated Thursday that he has "total" confidence in his attorney general, Ross remains skeptical.

The people at the DOJ conducting it know ultimately Sessions is their boss, and he'll be pleased or displeased with how they handle the investigation. — Constitutional lawyer Catherine Ross

If the Trump administration didn't already have a loose enough relationship with facts, what are voters to make of the most senior law enforcement official of the land making a false statement at a Senate confirmation hearing?

"He is a former attorney general of a state, with trial experience, and he didn't take the opportunity to correct or amend his sworn testimony. That disturbs me," Ross said. "It makes me much less comfortable about the answers he gave."

That the investigation into the Trump campaign's ties with Russia remains with the Department of Justice is no less comforting to those demanding an independent commission.

"The people at the DOJ conducting it know ultimately Sessions is their boss, and he'll be pleased or displeased with how they handle the investigation," Ross said.

Sergey Kislyak, Russia's ambassador to the U.S., has emerged as the central figure in the investigations into the Trump team's connections with Russia. (Cliff Owen/Associated Press)

Despite the furor, there doesn't appear to be much hand-wringing over whether Sessions is actually likely to be impeached under Article 2, Section 4 of the Constitution.

The section states the president, vice-president and all civil officers, including cabinet-level officers, are subject to impeachment and trial by Congress for "treason, bribery, or other high crimes and misdemeanours."

Ross notes that impeachment is limited so far in history to federal judges and the president.

Veteran Capitol Hill staffer and Democratic strategist Jim Manley, who spent 21 years in the Senate, was struck by how few Republicans he saw as willing to defend Sessions. This was the first time he saw conservative lawmakers in the party coalesce in a way to break from the administration.

"To date, Republicans have largely rallied around Trump," Manley said.

This time, key Republican lawmakers including Utah representative Jason Chaffetz, Ohio Senator Rob Portman and Maine Senator Susan Collins have broken ranks with the White House's line expressing absolute faith in Sessions.

"AG Sessions should clarify his testimony and recuse himself," Chaffetz tweeted on Thursday morning.

AG Sessions should clarify his testimony and recuse himself —@jasoninthehouse

Calling Sessions a "former colleague and a friend," Portman said in a statement that "it would be best for him and for the country to recuse himself from the [Department of Justice] Russia probe."

In an interview about Sessions, House majority leader Kevin McCarthy of California told MSNBC that for the "trust of the American people, you recuse yourself from these situations." (He later walked back his remarks, telling Fox News, "I'm not calling on him to recuse himself.")

There was good reason for Republicans to join the pile-on, Manley said.

"I think Republicans want to get this behind as soon as possible" to enact a packed agenda that includes the very tall orders of repealing and replacing the Affordable Care Act and overhauling the tax code, he said.

Out of the last 64 years, since Dwight Eisenhower was sworn in as president, there have only been six years in which a Republican White House had control of both houses of Congress. In 1954 Taylor's Bakery baked and decorated a cake for the president's 64th birthday at the Marion County Fairgrounds in Indiana. (Associated Press)

Gary Nordlinger, with the Graduate School of Political Management, has crunched the numbers. Out of the last 64 years, since Dwight Eisenhower was sworn in, there have only been six years in which a Republican White House had control of both houses of Congress.

Squandering this opportunity over "more Russia frustrations" would be a mistake, especially after Trump won a rare day of good press following his first speech before a joint session of Congress, Nordlinger said.

"Trump came off what appeared to be a successful speech for him, and now what's on the headline? It's Russia again."

For now, the attorney general's recusal has at least taken some immediate pressure off him politically.

"It's the most important thing he could have done for damage control now," Nordlinger said. "We'll have to see if it calms the predators down."