Image source, Getty Images

We're hearing now from Trump's defence team. First up is lead attorney Bruce Castor Jr.

With just over a week to go before the trial, Trump parted ways with his initial legal team, including attorneys Butch Bowers and Deborah Barbier.

They were quickly replaced by David Schoen, a trial lawyer, and Bruce Castor, a former district attorney.

You may remember Schoen from his work with another high profile client: former Trump adviser Roger Stone, who received a presidential pardon in December.

Schoen also made headlines in the past for meeting with Jeffrey Epstein in his final days to discuss possible representation, and for later saying he did not believe the death of the US financier and sex offender was suicide.

Castor, a former Pennsylvania district attorney, is known for declining to prosecute Bill Cosby for sexual assault in 2005. The comedian was eventually convicted on three counts of sexual assault in a 2018 retrial of his case.

Samantha Granville
BBC News, Capitol Hill

As Jamie Raskin took to the Senate floor on behalf of the Democrats, he promised not to give a lecture that would bore all of his Senate colleagues, but just lay out the facts instead.

He played a very moving ten-minute video, and it was clear he was trying to evoke the same emotion from the day Trump supporters entered the US Capitol.

The atmosphere in the chamber was incredibly tense while the video played. There’s no doubt all the senators were being transported back in time to when their chamber was turned into a crime scene just over a month ago.

As for Covid precautions during the trial? The senators' desks have bottles of hand sanitiser and Clorox wipes placed on them. Most senators and their staffers are wearing masks - with a notable exception of Rand Paul, who contracted the virus last year.

Senator Paul has been saying he’s immune after having Covid-19, but that statement is still scientifically not proven. Other senators, some who have had the virus and others who have been vaccinated, are still wearing their masks.

Lead manager Jamie Raskin has just wrapped up for the Democrats with an emotional address to his peers, sharing how 6 January had unfolded for him, his family, friends, staff members.

"I hope this trial reminds America how personal democracy is. And how personal is the loss of democracy, too."

Raskin tells the Senate his youngest daughter, 24-year-old Tabitha, was there with him on 6 January, to support him as they had buried her brother, Raskin's son Tommy, a day earlier.

He recalled the quickly escalating chaos of the day as the president's supporters invaded the Capitol.

"Our new chaplain got up and said a prayer for us and we were told to put our gas masks on and then there was a sound I will never forget: the sound of pounding on the door like a battering ram. the most haunting sound I ever heard."

He describes hearing people texting loved ones, whispering final goodbyes over the phone. He remembers seeing a rioter use a flag pole - with the US flag still on it - to spear an officer.

But most striking to him, Raskin says, was later on, when his daughter told him she did not want to ever come back to the Capitol.

"Senators, this cannot be our future."

Senators have reconvened after taking a short break. Here's a recap of what has happened so far:

• The trial began at 1300 EST (1800 GMT).
• Senators approved a resolution on the structure and rules of the trial, with 11 Republicans voting against it.
• The trial kicked off with lead impeachment manager Jamie Raskin playing a compilation of clips from the riot on 6 January.
• Raskin and his fellow prosecutors explained why the Senate has the right to hold a trial to convict the former president.

Joe Biden has been keeping a low profile, and as Congress is a separate political body to the White House, the president is not involved in former President Trump's impeachment trial proceedings.

Sitting in the White House next to Vice-President Harris, Biden says he is too busy to watch the trial:

Anthony Zurcher
BBC North America reporter

This was supposed to be the day of stuffy legal debate on the Senate floor, where House impeachment managers and Trump’s defence team wrangled over constitutional precedent and textual interpretation.

Instead, Jamie Raskin – the head of the House’s prosecution team – opened with a visual gut-punch.

If the Senate failed to put Trump on trial for inciting an insurrection against Congress, he said, “We risk allowing January 6 to become our future.”

Then he hit play on a video that walked step by step through that January day.

Donald Trump’s speech in front of the White House urging his supporters to fight.

The obscenity-spewing mob heading to the Capitol and confronting the security forces there. The building’s defence faltering, then breaking. The chaotic scenes as the Capitol was evacuated and a gunshot took the life of one of the rioters.

The video ended with Trump’s tweet that “these are the things and events that happen when a sacred landslide election victory is so unceremoniously & viciously stripped away from great patriots…”

Those words stood frozen on the screen for a moment. Then Raskin resumed his presentation.

"If that’s not an impeachable offense, then nothing is," he said.

The House prosecutors have to remind senators of the violence, fury and fear of that day if they have any hope of winning a conviction. They need to make a play to emotion, as well as reason. And in this case, a picture – or a video – is worth a million words.

Up next: impeachment manager David Cicilline. He was one of the two Democratic congressmen who began drafting the impeachment measure while sheltering in place during the riot.

Trump, Cicilline says, is not a "randomly selected private citizen" now being censured by lawmakers, but a former president, who is already treated differently as the one-time leader of the nation.

"For four years we trusted him with more power than anyone else on earth," he continues. "The former president who promised on a Bible to use his power faithfully. He can and should answer for whether he kept that promise while bound to it in office."

Cicilline adds that the danger of Trump has not "gone by".

Image source, Getty Images

Impeachment manager Joe Neguse wraps up his time with an impassioned reminder for his colleagues to remember what happened on 6 January.

"What you experienced that day, what we experienced that day, what our country experienced that day, is the framers' [of the Constution] worst nightmare come to life," Neguse - a rising Democratic star from Colorado - says.

"Presidents can't inflame insurrection in their final weeks and then walk away like nothing happened. And yet that is the rule that President Trump asks you to adopt.

"I urge you - we urge you - to decline his request. To vindicate the Constitution. To let us try this case."

Image source, Getty Images

Congressman Joe Neguse is the next Democratic impeachment manager to speak.

He's focusing on precedent as a reason why the Senate has the right to consider convicting Trump.

That begs the question: Which other presidents have been impeached?

Remember, Trump has already been impeached once before (he's the only president to have been impeached twice).

The two others who have faced such censure are Bill Clinton in 1999 and Andrew Johnson way back in 1868. But none were ever convicted by the Senate.

Want to know more? Check out our guide on impeached presidents here.

Anthony Zurcher
BBC North America reporter

Just a few minutes into Donald Trump’s Senate impeachment trial, and it’s already clear that the former president’s most loyal defenders are digging in.

During consideration of the bipartisan resolution setting out the ground rules for the trial, 11 Republicans voted no.

They included Josh Hawley of Missouri and Ted Cruz of Texas, two of the most outspoken supporters of Trump’s efforts to challenge his general election loss.

Also opposed were Rand Paul of Kentucky, who introduced a resolution last week to dismiss the case against Trump, and Ron Johnson of Wisconsin, another of the president’s ardent defenders.

These 11 senators are also regular “no” votes on Joe Biden’s picks to fill cabinet posts. Hawley has voted against all seven nominees considered by the Senate so far. Cruz has rejected five.

Some of the senators, like Cruz and Hawley, have 2024 presidential ambitions. Others, like Bill Hagerty of Tennessee and Tommy Tuberville of Alabama, come from very conservative states that overwhelmingly support Trump. Call them the scorched-earth caucus.

With at least 11 Republicans in favour of shutting the trial down before it even starts, it means 17 of the 39 remaining of them would have to side with all 50 Democrats to convict.

Lead Democratic impeachment manager Raskin is now detailing why holding a trial now is still constitutional and necessary, although Trump is no longer president.

Raskin says the founders' goal was "always about accountability, protecting society and deterring official corruption" rather than removing someone from office.

What else are Democrats planning to say?

We reported on Monday that Trump's lawyers rejected the claim that the ex-president incited insurrection in a speech to his supporters, pointing to FBI evidence that the riot was planned days in advance.

Impeachment team lawyers responded, external just ahead of today's proceedings.

Suggesting that Trump has "no good defence", they will argue that he has tried to "shift the blame onto his supporters". They also repeat their claim that Trump had been stoking violence from his supporters for weeks in his repeated, baseless claims of election fraud.

Addressing the argument, expected to be one of Trump's core defences, that the trial is unconstitutional, the Democrats wrote: "It is inconceivable that the Framers designed impeachment to be virtually useless in a president’s final weeks or days, when opportunities to interfere with the peaceful transfer of power are most present."

The trial has kicked off very differently than Trump's first impeachment.

For the last ten minutes, lawmakers have been shown a compilation of clips put together by Democrats from the events of 6 January.

It began with Trump's speech and included visuals of rioters breaking into the building and fighting with Capitol police - from all angles.

"Senators, the president was impeached on 13 January for everything we just saw," Raskin says. "If that's not an impeachable offence, then there's no such thing."

Here's our own look back at what happened that day.

Image source, EPA

We're hearing from lead impeachment manager Democrat Jamie Raskin (the managers are the House lawmakers acting as prosecutors).

He says that tossing this impeachment trial aside, as Trump's lawyers are arguing lawmakers should do, would mean setting a "dangerous" precedent.

It would be, Raskin says, "an invitation to the president to take his best shot at anything he may want to do on his way out the door including using violent means to lock that door, to hang on to the Oval Office at all costs and to block the peaceful transfer of power.

"In other words, the January exception is an invitation to our founders' worst nightmare."

He's now playing a compilation of clips from the day of the Capitol attack, as well as Trump's speech before the rioting began.

Alright, the resolution on the rules has been approved, so it's a good time for a quick refresher before arguments over constitutionality begin.If you've got questions on what this trial is all about, who's involved and what happened on 6 January - we've got you covered. Check out our explainers below.

• What is Trump accused of?

• Who are the key players?

• Did Trump's words incite a riot?
• The other impeached presidents

The US Senate is broadcasting proceedings on a livestream from their website.

You can watch the trial here., external

Image source, EPA

We just heard from Democratic Leader Chuck Schumer, who said these were the "gravest charges ever brought" against a president.

The senators are voting first on a resolution as to how the trial will proceed.

This has already been agreed to by impeachment managers, Trump's counsel, and both political parties, Schumer notes.

We're now hearing a roll call vote play out on these trial rules.

The Senate begins proceedings with a prayer from the chamber's chaplain, followed by the US Pledge of Allegiance.

With that, opening business is closed, and Democrat Leahy sounds the gavel.

The second impeachment trial of Donald Trump has started.

It's now just minutes to go before the Senate begins the historic second impeachment trial of Donald Trump. Here's what to expect:

• The gavel drops at 1300 EST (1800 GMT) with Democrat Patrick Leahy chairing over the session
• But before we get to the actual trial, senators will debate whether holding a trial is constitutional or not, as Trump is no longer in office
• After four hours of back-and-forth, the Senate will vote - and a simple majority (more than 50) would allow the trial to go ahead

Nomia Iqbal
BBC News, Washington

Up to 27,000 troops from the National Guard came into DC for the inauguration and around half are still here for the duration of the impeachment trial.

Tall metal fencing surrounds the Capitol with barbed wire at the top and armoured vehicles in position.

One soldier tells us he has real mixed emotions about being here.

"It's exciting to be in the nation's capital and see the government at work but at the same time it's surreal."

"Are we really in the US or are we overseas on duty? That's how it feels sometimes," he said.

Troops are expected to remain here into March due to plans by QAnon members - conspiracy theorists loyal to Donald Trump - to protest in the city.

They will be on guard to avoid a repeat of the riot that happened on 6 January.

Chelsea Bailey
Digital producer, BBC News

Is there any chance that two-thirds of senators will support the impeachment? - Zohmaa, India

We should always leave room for surprises, Zohmaa! But as we head into the trial it looks as though the odds of having two-thirds of the Senate back Trump’s conviction are very slim.

The current Senate is made up of 50 Republicans, 48 Democrats and two independents (who often work alongside the Democrats). This means if every Democrat votes to convict Trump, you’d still need 17 Republicans in order to convict.

During Trump’s first impeachment trial only one Republican – Senator Mitt Romney of Utah – voted to convict him. A lot has changed since then and several prominent senators have criticised Donald Trump’s actions, but it’s unlikely that will translate into 17 votes.

Image source, Getty Images