Editor’s Note: This story was originally published in December 2018 before former FBI director Robert Mueller concluded his special counsel investigation into Russia’s election interference. It has been updated.

CNN  — 

Many Democrats viewed Robert Mueller’s public comments on Wednesday as passing the baton to them to start impeachment proceedings against President Donald Trump.

Mueller, who spoke publicly about his two-year special counsel investigation for the first time in a surprise news conference, said he could not clear the President of obstruction of justice. But he declined to follow the example of Ken Starr, the independent counsel who offered a detailed guide to impeaching President Bill Clinton in 1998.

That leaves Democrats still at odds over how to deal with Trump.

Rep. Jerry Nadler, who chairs the House Judiciary Committee, and House Speaker Nancy Pelosi have stopped short of saying Democrats would pursue impeachment, but they are clearly under pressure from some in their party since the release of the Mueller report.

“Nothing is off the table,” Pelosi said during an appearance in San Francisco, arguing that Democrats need to get all the facts.

“Mr. Mueller told us a lot of what we need to hear today,” Nadler said during a news conference, suggesting he may not need to subpoena Mueller for his committee’s investigation.

If Democrats do decide to impeach Trump, the process would involve a series of complicated steps. Here’s a look at how it would work.

(Click for a more in-depth explanation.)

Is impeachment remotely possible?

According to the US Constitution, impeachment proceedings start in the House, then they have to go to the Senate for a trial.

Democrats control the House, so they could vote to investigate and impeach Trump on a simple party line.

Then it would go to the Senate, where it takes a two-thirds majority to find a president guilty of high crimes and misdemeanors. That’s 67 senators if everyone votes. Republicans control the Senate, so they’d have to break with a President from their own party in a very big way. How big? Twenty Republicans would have to cross the aisle and join 47 Democrats. That seems like a tall order. So far, Rep. Justin Amash of Michigan is the only congressional Republican who has sounded open to impeachment.

Plus, a lot of Democrats, notably Pelosi, can remember when impeaching Clinton backfired on Republicans in the late 1990s. Clinton was popular overall, despite his infidelity and his lies about it. The Republican House impeached him, but nowhere near 67 senators voted to kick him out of office. He reached the height of his popularity as President when the effort was seen as a partisan attack. Every Democrat stayed with Clinton in the Senate and even a few Republicans voted against convicting him.

It was a different story for Richard Nixon, who resigned from office in August of 1974 rather than be impeached. In his case, his popularity then was far lower than Trump’s is now. Members of his own party were starting to turn against him and he had no choice but to resign or probably be kicked out of office.

President Richard Nixon reading a farewell speech to his staff following his resignation in August of 1974.

That’s exactly why Trump has tried to paint the special counsel’s investigation as a “witch hunt.”

If Trump were, somehow, impeached and removed from office, Vice President Mike Pence would become president.