Speaker of the House Nancy Pelosi ignited the chattering class this week by stating: “Impeachment is so divisive to the country that unless there’s something so compelling and overwhelming and bipartisan, I don’t think we should go down that path, because it divides the country. And he’s just not worth it.”  Trump and his supporters were quick to read full exoneration into her comments.  In reality, the statement should have no effect on the work of the House of Representatives.  It means that impeachment makes no sense before we’ve seen what emerges from Mueller and the oversight work of the committees.  At some point down the investigative road, the House will decide whether to begin formal impeachment proceedings.

Impeachment done properly is a lengthy, deliberate, and careful process.  It is already underway and nothing Pelosi said will stop it.  The House Judiciary Committee’s requests for documents from eighty-one entities, and investigations by the House Intelligence Committee, the Committees on Oversight and Reform, Ways and Means, Financial Services, and others are the necessary precursors to a formal impeachment effort.

The effect of Pelosi’s statement is more political than operational.  She provides cover for moderates in her caucus, who shy away from impeachment, while assuming the heat for her left flankers, who can profess to their constituents their desire to impeach immediately and blame leadership.  The statement also makes it marginally more difficult for Trump and his supporters to accuse Democrats of pursuing baseless impeachment charges under the guise of oversight.

That said, Pelosi’s statement should be interpreted as simply stating an appropriate standard for moving to the final stage of impeachment.  The evidence should be sufficiently compelling and overwhelming to garner bipartisan support.  The way to develop that evidence is to conduct intensive oversight investigations that will lay the facts before the public in indisputable form.  Politicians will follow the public.

The big mistake would be to call the game now, before the investigation.  While out of power, Democrats had to fall back on admonitions to wait for Mueller’s report.  Yet, as the House begins its oversight, well over 40% of the public thinks Trump should be removed from office.  The combination of congressional investigations and release of the fruits of Mueller’s investigation surely will drive up that number.

The lessons of history must be interpreted through the lens of changed times.  The emergence of a presidential propaganda network, development of social media, a deepening partisan divide, gerrymandering, and the uniqueness of Trump all matter, but past impeachment experience remains instructive. It suggests that Democrats should not be overly fearful of beginning the process and may have more to lose if they don’t.

When Nixon took the oath for his second term in January 1973, his approval stood at 68% and there was no talk of removal. When the Senate Select Committee launched its hearings in May of that year and Archibald Cox was appointed special counsel, only 19% favored Nixon’s removal from office and his favorability rating hovered in the high 40’s.  By August, after a summer of hearings, his approval had fallen to the low 30’s, yet still only 26% thought he should be forced from office.  That number jumped to 38% by November, following the October firing of Cox and hovered in that range when the House gave the Judiciary Committee formal authority to start an impeachment inquiry on February 6, 1974.  It had risen to 44% by June 1974, when House impeachment proceedings were well under way, but did not pass 50% until late July, when the House Judiciary Committee approved three articles of impeachment. The combination of public testimony and the parallel special counsel investigation, which forced production of the smoking gun tapes, finally convinced the public it was time for Nixon to go.

Not a single Republican senator would vote today against Trump.  But, at the equivalent stage, Republican senators were not stepping up to convict Nixon.  Sen. Howard Baker initially asked his famous question – what did the president know and when did he know it? – to protect Nixon by emphasizing that witnesses could not produce direct evidence against him.  Indeed, he discussed inside information with the Nixon White House through the Senate hearings.  When the House Judiciary Committee finally adopted three articles of impeachment, a majority of Republicans voted against each.

Conventional wisdom holds that Republicans hurt themselves by impeaching Bill Clinton.  While Clinton’s popularity rose after impeachment, Republicans (other than Newt Gingrich who was ousted as Speaker) also prospered.  They held onto their congressional majorities and elected George W. Bush in the next presidential election.  The impeachment surely played a role in the defeat of Al Gore, who felt the need to distance himself from Clinton, and the events that the impeachment publicized stayed with Hillary Clinton through her runs for office.

Notably, Democrats won the presidency after Nixon’s resignation and Gerald Ford’s pardon of Nixon damaged his election prospects.  By contrast, Speaker of the House Jim Wright prevented the House from moving to impeach Ronald Regan in the wake of the Iran/Contra scandal.  As the facts of the scandal emerged, impeachment became a real possibility.  In the absence of impeachment, Reagan’s approval increased and Republicans won the 1988 presidential election.  Wright later admitted that it might have been an error to squelch impeachment.

The central factor distinguishing Trump from his predecessors is that he appears to have engaged in far more egregious and widespread wrongdoing.  Nixon covered up a burglary and Clinton lied about sex, but Trump may have, among other acts, conspired with a hostile power to win the presidency, violated the Emoluments Clause, violated campaign finance laws, and engaged in numerous acts to obstruct the investigation of his conduct.

In this context, principle also counts.  Impeachment is the essential constitutional guard against a tyrannical or criminal executive.  Allowing egregious conduct to go unaddressed poses the danger of raising the bar so high for impeachment that it can never be invoked.  Similarly, refusing to begin the investigative process until there is bipartisan support creates a partisan veto of a constitutional function.

For now, the House will continue demanding documents and testimony.  The administration will resist.  Courts almost certainly will be asked to further define the scope of executive privilege.  Eventually, the House will have to decide whether to launch formal impeachment proceedings.  At that point, the Pelosi test can be applied.

Bill Yeomans is the Senior Justice Fellow at Alliance for Justice. He currently serves as Lecturer in Law at Columbia Law School, and previously taught constitutional law, civil rights, and legislation at American University Washington College of Law. He also served for 26 years in the Department of Justice, where he litigated cases involving voting rights and discrimination in employment, housing, and education, and prosecuted police officers and racially motivated violent offenders before assuming a series of management positions, including acting Assistant Attorney General. For three years, Bill served as Sen. Edward M. Kennedy’s chief counsel on the Senate Judiciary Committee, and has also held positions at AFJ and the American Constitution Society.