Donald Trump is floating impeachment to rev up his base. Here's why that's still a stretch.

They're using the threat of impeachment to get out the vote and almost daring Democrats: Go ahead, impeach this guy.

Both President Donald Trump and Senate Majority Leader Mitch McConnell brought it up in recent days.

"I don't even bring it up," said Trump at a rally in Montana, as he launched into a riff on the subject. "Because I view it as something that, you know, they like to use the impeach word. Impeach Trump. Maxine Waters, 'We will impeach him.' But he didn't do anything wrong. 'It doesn't matter, we will impeach him. We will impeach.' But I say, how do you impeach somebody that's doing a great job that hasn't done anything wrong?"

The President warned that impeaching him would lead to a sort of impeachment-off against successive administrations. He also issued a warning to his supporters: If you don't vote, he suggested, I'll get impeached.

"But we'll worry about that if it ever happens. But if it does happen, it's your fault, because you didn't go out to vote. OK? You didn't go out to vote. You didn't go out to vote. That's the only way it could happen. I'll be the only president in history -- they'll say what a job he's done. By the way, we're impeaching him."

And McConnell's impeachment reference came during an interview with the conservative host Hugh Hewitt, who asked about whether a President could be indicted.

"I'm a lawyer, but not a good one. ... The Justice Department, I gather, has taken the position under a president of both parties that the appropriate remedy for presidential misbehavior is impeachment," McConnell told Hewitt in a taped MSNBC interview. "I'm not an expert on this, but I hear that's the case."

Democrats, meanwhile, have shied away from the idea. Nancy Pelosi, who really wants to be speaker of the House again, and if Democrats took control of the House, would basically have the ability to quash an impeachment effort, said last month it would only help Republicans and Trump.

"I don't think we should be talking about impeachment. I've been very clear right from the start," Pelosi said recently on Capitol Hill. "On the political side I think it's a gift to the Republicans."

The country, by the way, has inched toward favoring impeachment for Trump, but they're still a ways off from agreement.

Forty-nine percent of Americans supported beginning impeachment proceedings in an ABC News / Washington Post poll at the end of August. Democrats (75%) were strongly in favor and Republicans (82%) were strongly opposed. Independents were more evenly split.

In a CNN poll from June, 42% of Americans said Trump should be impeached. But that's about the percentage who supported impeaching Nixon in 1974 when he resigned as the House moved against him. A larger percentage support impeaching Trump now than supported impeaching Trump then. But Nixon faced a hostile Congress controlled by Democrats. Impeaching Trump would, he's right, basically require a Democratic majority and unanimity within the party. But removing him from office would take a Senate supermajority. Even if Democrats took control of the Senate in November, which is a long shot, they'd be nowhere near that 67 votes needed to remove him from office.

All of this is to say that while Trump wants to raise the specter of impeachment to fire up his base supporters before election day, we still feel a very long way away from a serious impeachment effort and it would almost certainly depend on what kind of report, if any, is released by special counsel Robert Mueller with regard to Russian campaign interference and possible collusion by Trump's campaign or something else that could fall into the "high crimes and misdemeanors" category.

With that important disclaimer, here's what would have to happen:

It's a complicated process

Considering how short the document is, the Constitution takes up quite a bit of space on the matter, spelling things out for the House, the Senate and the Executive in Articles I and II.

In Article I, Section 2:

The House of Representatives shall chuse their Speaker and other Officers; and shall have the sole Power of Impeachment.

In Article II, Section 3:

The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two thirds of the Members present.

Judgment in Cases of impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.

In Article II, Section 4:

The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.

In plain English, that means first, there needs to be evidence that Trump committed treason, bribery or high crimes and misdemeanors. Not just any crimes and misdemeanors, mind you. High ones. For Clinton, he was accused of perjury and obstruction of justice. For Nixon, list was longer and passed through a House committee as part of three articles. Regardless, it is an extremely broad and subjective target and there's been a lot of scholarship about exactly what it means. This country has historically shown a willingness to give its chief executive a lot of latitude. So, what next?

How would it happen?

The full House would authorize one of its committees, usually the judiciary committee, to investigate and consider impeachment, according to an overview from the Congressional Research Service.

That committee conducts an investigation and draws up articles of impeachment.

They then vote in that committee on whether to refer some or all of the articles to the full House.

If the committee votes to impeach, they prepare a report for the full House, which then debates and votes on the articles. The House can approve some of the articles and not others. In the case of Bill Clinton, for instance, two of four articles were approved by the full House.

If the full House votes for impeachment on a simple majority, the approved articles are then referred to the Senate, which conducts a trial. Chief Justice John Roberts would preside, according to the Constitution. Members of the House lead the prosecution and senators are jurors.

Senators then meet in closed session and vote on whether to convict and remove from office. A conviction requires a two-thirds majority. That's 67 senators. Sixty-seven!

Republicans control the House and Senate

Both Nixon, who wasn't actually impeached, and Clinton, who was impeached by the House but acquitted by the Senate, were facing off against a hostile Congress controlled by the opposing party. So was Andrew Johnson, the Democratic vice president who succeeded Abraham Lincoln as president after his assassination and was impeached by the hostile Republicans who controlled Capitol Hill. He was acquitted too. Got that? the Senate is 0-for-2 on convicting presidents from the other political party.

Republicans -- Trump is a Republican, remember -- have a 237-193 majority in the House. That means 20 or more Republicans, depending on who is voting, would have to break ranks to impeach their Republican President.

Those numbers will obviously change after election day, and that's when you might hear Pelosi change her tune on impeachment, especially if Democrats can achieve a large majority. The smaller the majority, the less feasible impeachment would be. If Republicans keep the House, impeachment seems essentially off the table.

The House, however, is the easy part.

Republicans currently have 51 senators, so 19 of them would have to break ranks and vote to convict a Republican president, assuming all Democrats voted to do so.

Nixon, by the way, resigned before impeachment went to a vote in the full House of Representatives. In that case, most of the Republicans on the judiciary committee opposed the articles.

Republicans have not turned on Trump

There is not even a critical mass of Republicans who think there should be a special prosecutor to investigate the Trump campaign's ties to Russia. Exactly zero Republicans have said anything close to supportive of impeachment. Trump is likely to be protected by his Republican allies in the Senate even if Democrats gain majorities in both houses and decided to try to impeach him.

Impeachment is extremely rare

Just 19 people -- two presidents, one senator, one secretary of war and 15 judges -- have been impeached by the House and tried in the Senate. Of those, only eight were convicted. Seven, including both impeached presidents, were acquitted. Charges were dropped against three others after they were either expelled from office or resigned.

Most officials who get to the point of impeachment would rather resign a la Nixon than face a public trial in the Senate. The US also has regular elections, including the midterms in November and Trump's planned bid for re-election in 2020. A representative or senator is more likely to be expelled from their respective body by their peers or kept from re-election by the voters.

It takes a long time

The impeachment process takes months and months. There are years of this administration in front of us, but the impeachment process would seem like an eternity in the Trump era if the current pace of news keeps up. The House first voted to consider impeaching Nixon in February 1974. The House judiciary committee didn't vote on an article of impeachment until July 24. Nixon resigned on August 8 of that year before the full House had voted.

In the case of Clinton, the House judiciary committee began considering whether to impeach Clinton on September 24, 1998 and they voted to refer articles of impeachment to the full House months later on December 11 and 12. He was impeached by the full House on December 19, although they rejected several articles suggested by the judiciary committee.

Clinton was acquitted by the Senate, although a majority voted against him, on February 13, 1999.

Interesting note for Democrats: Impeachment is a political tool, not a criminal one, and it can backfire. Democrats picked up five seats in the House in the 1998 midterm elections despite the unfolding scandal and impeachment! Trump seems to be banking on a similar sort of backlash by bringing it up now.