Democratic Committee Chairman Adam Schiff has now concluded, speaking from the lectern without notes.

"What is at risk here is the very idea of America. That idea holds that we are a nation of laws, not of men. We are a nation that believes in the rule of law."

The debate is finished and voting has now started on the first article of impeachment - abuse of power. That will take about 15 minutes.

Back in Battle Creek, Michigan, Vice-President Mike Pence has just taken to the stage for that Trump rally.

He was greeted by cheers as he said "well hello Michigan - and Merry Christmas".

It didn't take long for him to get onto the subject of the day.

He said, like those at the event, when the "do-nothing Democrats" continue with their "endless investigations and partisan impeachment", they "stand with President Donald Trump".

There are boos when he says Nancy Pelosi and the Democrats are having their say tonight - but that the Senate will have their say in January.

"Voters will remember in November," he says.

Image source, Getty Images

One of those thought to be voting no to the impeachment articles is Democrat Jeff Van Drew, who is expected to then flip his allegiance and join the Republican Party.

Members of his staff have quit in protest - and six have now been offered new jobs, external with a New Jersey Democrat, local media reports.

Van Drew told reporters he moved to stand on the Republican side of the aisle for the debate as it was "appropriate", Fox News reported, external.

The representative for New Jersey's 2nd congressional district said the impeachment process was "how an oligarchy operates... it is how third-world countries operate".

"The vote is what counts," he added.

He's said his announcement on switching parties will come "very shortly" - but not on Wednesday.

Democratic presidential hopeful Cory Booker has accused Van Drew of putting his re-election prospects first.

Van Drew won the open New Jersey US House seat in 2018 for the Democrats, but it had been held by a Republican since 1995 prior to that.

Hundreds of members of the public are waiting to get in to the floor of the House so they can be in the room when the impeachment vote happens.

ABC7 News reporter Lindsey Mastis said people told her they'd been waiting for hours to get in.

We're getting ever closer to the crucial vote here.

The BBC's Anthony Zurcher is watching proceedings unfold.

The president's press secretary tweeted this picture of him arriving in a chilly Michigan a little earlier.

His eager supporters are waving festive green, white and red campaign banners as they await his arrival in Battle Creek.

There will be two votes shortly - one for each article of impeachment.

Trump is charged by the House with abuse of power and obstructing Congress.

The vote on each article of impeachment is expected to last approximately 20 minutes.

First comes abuse of power, then obstruction of Congress.

If either vote passes with at least 216 lawmakers voting in favour, Trump will be the third ever impeached president.

It will then be up to the Senate to hold a trial, which is expected in January. Because Republicans control that upper chamber, it is highly unlikely that he will be convicted and removed from office.

An all that action is expected to come before 20:00 Washington time (01:00 in the UK).

After the vote is held, both Democrats and Republican will deliver news conferences.

"In 2016, I along with 63m American voters... went to the polls and we raised our collective political middle finger to DC and voted for Donald Trump," says Republican Drew Ferguson.

He goes on to condemn "the liberal elites, the condescending bureaucrats and every other kind of swamp critter in this godforsaken place," who he says are trying to change the outcome of the 2016 election, which brought Trump to power.

"This whole flippin' goat rodeo is a sham and a shame, and it will not be forgotten," adds the Georgia lawmaker.

As the dramatic moment nears - when Trump will almost certainly become the third president in US history to be impeached by Congress - tune into BBC World News for live rolling coverage of the vote.

Where and how to watch BBC World News

A rumour doing the rounds in Washington says the House of Representatives might delay sending the articles of impeachment to the Senate for a trial once they are voted through later tonight.

There's a bit of a murky legal debate about whether the House vote itself begins the Senate process, or if representatives of the House have to formally "deliver" the articles of impeachment to the Senate, writes the BBC's Anthony Zurcher.

Trump impeachment - your questions answered

This is noteworthy because there's been some speculation that House Speaker Pelosi could hold back the impeachment articles until she is convinced the Senate will conduct a fair trial, or to allow further investigations of the president.

That seems an unlikely outcome, but these days if a rule isn't written in ink there's always the chance it's not really a rule after all.

"Some think it’s a good idea. And we need to talk about it," said House Democratic Leader Steny Hoyer as today's debate began.

The idea has grown more popular among some lawmakers in recent days as an article circulated in which constitutional lawyer Laurence Tribe argued that Democrats should withhold the articles in order to secure assurances from Republicans.

A spokesman for Senate Republican Leader Mitch McConnell, who will set the rules of the Senate trial, cheered the rumour with a tweet.

Image source, Getty Images

Republicans have taken flak for comparing Trump's impeachment to the crucifixion of Christ, the surprise Japanese attack at Pearl Harbor in WW2 and the Boston Tea Party.

But Republicans are also criticising Nancy Pelosi for comparing the articles of impeachment to the WW2 Battle of the Bulge, which happened 75 years ago last week.

In her opening statement, she described travelling to Europe with other US lawmakers "to express our gratitude to the heroes who sacrificed everything to secure victory of freedom over tyranny, not just for America, but for the world".

Quoting late Congressman Elijah Cummings, she said: "When the history books are written about this tumultuous era I want them to show I was among those in the House of Representatives who stood up to lawlessness and tyranny."

"Today we are here to defend democracy for the people. May God bless America," she said in closing.

The battle lasted for two months and led to the deaths of nearly 20,000 US soldiers.

Writing in conservative blog Breitbart News, Joel Pollak writes that "Pelosi was right, in one sense: the Battle of the Bulge was the last-ditch effort of a determined enemy of freedom to stave off inevitable defeat".

Image source, Getty Images

Image source, Getty Images

Those glued to the impeachment debate may have heard reference to Alexander Hamilton during the day.

Adam Schiff, House Intelligence Committee Chair, quoted his warning about a man "unprincipled in private life, desperate in his fortune, bold in his temper" who would "throw things into confusion".

"Hamilton seems to have predicted the rise of Donald Trump with staggering prescience," he concluded.

Republicans and Democrats have both used words from Hamilton - the United States' first secretary of the treasury - to back up their impeachment stance.

His name was mentioned 35 times in the 658-page report recommending the president's impeachment, the Washington Post reported.

Image source, Getty Images

But who (for those not lucky enough to have seen Lin-Manuel Miranda's musical Hamilton) was Alexander Hamilton?

Well, he was a statesman, a politician, one of America's founding fathers, developed the nation's financial system, and was instrumental in ending the legality of the international slave trade.

This BBC Business video explains more.

Lin-Manuel himself has been tweeting today:

The House of Representatives is holding a debate into whether to impeach Trump for "high crimes and misdemeanours" the language used by the US constitution to define an impeachable offence.

A formal vote is expected in the next two hours.

If both articles of impeachment pass as expected - the Democrats have the majority in the House - Trump will become the third president in US history to be impeached. But he will not be removed from office unless he is convicted in the Senate - unlikely given that the chamber is controlled by Republicans from his own party.

Trump is accused of abusing the power of the presidency by soliciting Ukraine to help him investigate his political opponent, Joe Biden; and obstruction of Congress for not co-operating with the House impeachment inquiry.

Trump denies any wrongdoing. Republicans say today's vote is the culmination of an effort to kick him out of office which began on the day that he was elected.

Democrats say he must be urgently punished, due to the imminent threat he poses to the 2020 election.

Around the same time as the votes, Trump will be holding a big rally in Michigan.

Let's take a wider look at what's going on.

Here you can catch up with all things impeachment-related.

SIMPLE GUIDE: If you want a basic take on what's going on, this one's for you

GO DEEPER: Here's a 100, 300 and 800-word summary of the story

WHAT'S IMPEACHMENT? It's a political process to remove a president - video guide

THE VIEW FROM TRUMP COUNTRY: Hear from residents in West Virginia

WHO'S WHO: A guide to the key players in US and Ukraine

A BUMPY RIDE: A newly elected Democrat sells impeachment to constituents

CASE FOR & AGAINST: What legal scholars are saying

Democrats have just announced that they will hold a news conference after the impeachment vote is held.

Speaker of the House Nancy Pelosi will be joined by the chairmen and chairwomen of the various House committees that drafted the articles of impeachment.

We've had a few more pictures in now of President Trump leaving a rather Christmassy-looking White House, as he heads towards Michigan.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

"It is unclear who will judge those voting on impeachment today more harshly; history or voters," says Pennsylvania Republican Fred Keller.

"So I want Democrats voting for impeachment today to know I will be praying for them," he continues.

He goes on to quote Jesus in the Gospel of Luke saying: "Father forgive them, for they know not what they do."

This is at least the second allusion to the crucifixion of Christ in this debate.

Earlier, another Republican claimed that Jesus' trial had been more fair than the one Trump is expected to face.

President Trump has left the White House in Marine One and is on his way to that Michigan rally, where he will face thousands of his fans this evening.

He didn't stop to speak to the press - though he did do a thumbs-up - choosing instead to speak to supporters waiting to see him.

He is likely to be on stage when the result of the vote on his impeachment comes out.

Trump campaign communications director Tim Murtaugh is delighted by this turn of events, however.

He told CBS News his party is keen for the split-screen moment as "the visuals are pretty bad for the Democrats".

What viewers will see, he explained, is the president surrounded by thousands of loyal supporters on one side - while on the other, there is a "drab" image of Democrats trying to stop his progress.

While he does not want to be impeached, this gives him the opportunity to immediately fight back.

Rather than harm him, the campaign "strongly believes" impeachment will help Trump win in 2020.

But how, when he is speaking at the rally, will Trump find out what has unfolded, thousands of miles away in Washington DC?

Murtaugh would only say that "one way or another, he will find out".

Image source, Getty Images

One person who's been busy on Twitter today is lawyer George Conway - the husband of White House adviser Kellyanne Conway.

He'd started by saying it was a "good day for the Constitution of the United States".

Conway went on to retweet a number of anti-Trump posts, including one showing the president's interview with CNN's Wolf Blitzer in 2008 in which he praises Pelosi and says George W Bush should have been impeached.

"He's a fraud and always has been," commented Conway.

He also retweeted Trump's reaction to the debate, in which he denounced the "atrocious lies by the radical left", with the words: "You seem unhappy."

Worth noting that while he was doing all this, Kellyanne Conway was at the White House giving press briefings.

She told reporters that the impeachment was "ridiculous" but that Trump did not see it as a "stain" on his legacy. She added it was a "conclusion in search of evidence".

Democratic White House candidate Julian Castro tweets that he is watching as his twin brother casts his ballot in today's historic vote.

"Getting caught doesn’t get you off the hook," said his brother, Texas Congressman Joaquin Castro, on the House floor minutes ago.

His remark refers to the fact that US aid to Ukraine was released despite a delay. Democrats say the delay was a bargaining chip the White House dangled over Ukraine in exchange for political investigations into his domestic rival.

Republicans say the military aid did get released, but Democrats charge that this was only because Trump got caught in the act.