Early on Thursday NZ time, the Trump impeachment inquiry kicks into high gear, as the previously closed-door proceedings are replaced with televised public hearings. Here’s the lowdown.

What’s about to happen?

Just over seven weeks since Speaker of the House Nancy Pelosi announced an impeachment inquiry into Donald Trump’s dealings with Ukraine, televised hearings are set to begin in a few hours’ time. Key players in the scandal will be questioned about the events leading up to the whistleblower’s original complaint about the Trump-Zelensky phone call, and about what was done in the immediate aftermath of that disastrous conversation.

Trump, Zelensky, Ukraine…remind me what that’s all about?

On July 25, in a phone call between Trump and newly elected Ukrainian president Volodymyr Zelensky, Trump pressed Zelensky to investigate the allegedly corrupt activities of Hunter Biden, former vice president Joe Biden’s son, while Hunter was on the board of Ukrainian natural gas company Burisma. Trump also asked Zelensky to “get to the bottom” of a conspiracy theory that the server containing Hillary Clinton’s deleted emails is somewhere in Ukraine. Both allegations have already been found to be entirely untrue.

At the time of the phone call, the White House had mysteriously frozen US$400m in Ukrainian military aid. Ukraine desperately needed the funds to support the ongoing war effort against invading Russian forces in eastern Ukraine.

The whistleblower, a CIA official who was listening in on the call, said Trump had made an explicit, and highly improper, request for Ukraine to investigate his political rivals – and also an implicit quid pro quo: do this for me, and you’ll get the money.

Following the release of the “transcript” (not technically a transcript) of the phone call on September 26, it emerged the Trump administration had been pressuring Ukraine to investigate Hunter Biden for months prior to the phone call.

Haven’t we already had hearings on all this?

Yes, but so far they’ve been so-called closed door hearings, held in private before members of the House intelligence, foreign affairs and judiciary committees. During those hearings, key US officials corroborated the whistleblower’s report, and added even more damning testimony. The picture that emerged was one of US diplomats sidelined in favour of a “snake pit” of Trump associates, in particular his lawyer Rudy Giuliani who has extensive business interests in Ukraine. Marie Yovanovitch, former US ambassador to Ukraine, testified that she’d been removed from her post for resisting Giuliani’s meddling and was forced to flee the country after receiving warnings that her safety was in jeopardy.

Even initially Trump-friendly witnesses ended up kicking the president in the shins. Gordon Sondland, the US ambassador to the EU who insinuated himself the US-Ukraine affair, originally testified that there had been no quid pro quo on Trump’s side. But when a string of witnesses – including Ukraine expert and decorated war hero Alexander Vindman – said the opposite was in fact true, Sondland revised his testimony. Claiming his recollection had subsequently been “refreshed”, he said he now remembered telling a senior Ukraine official that they probably wouldn’t receive the aid until a Biden investigation was launched.

While the closed door hearings proceeded smoothly for the most part, they descended into chaos on October 23 when Trump acolyte Matt Gaetz and around 25 fellow Republican congressmen crashed the secure room in which they were being held, a massive breach of both protocol and security that delayed hearings for several hours.

If we’ve already had hearings, what’s the point in doing it again?

One word: television. The Democrats hope that having witnesses testify on live TV will move public opinion in a way that no amount of written testimony ever could. If you’ve been following the inquiry so far, you shouldn’t expect many bombshell revelations over the next few days. As long as the witnesses say on camera what they said to committee members behind closed doors, that’s good enough for the Democrats.

So how’s it going to work? 

The hearings will kick off at 4am on Thursday NZ time. After opening statements, lawyers are expected to take over for 90 minutes of sustained questioning of witnesses, 45 minutes each for the Republican and Democrat sides. Previous live hearings gave congress members just five minutes each to ask questions, a frustrating system that encouraged the questioner to grandstand and allowed unwilling witnesses to run out the clock.

Day one of the hearings (day two is on Saturday NZ time) will feature Bill Taylor, who replaced Yovanovitch as ambassador to Ukraine, and George Kent, a senior diplomat and Ukraine specialist. Taylor’s appearance is expected to be particularly powerful, given that his closed door testimony elicited shocked “sighs and gasps” from committee members. Taylor is sure to be asked about the now-infamous text message chain between key officials – including man of the moment Gordon Sondland – following the Trump-Zelensky phone call. Taylor: “I think it’s crazy to withhold security assistance for help with a political campaign.” Sondland: “Bill, I believe you are incorrect about President Trump’s intentions. The President has been crystal clear: no quid pro quo’s of any kind.” With even Sondland himself now admitting that was untrue, expect fireworks tomorrow – and some extremely angry Trump tweets.

Sounds great, where can I watch it?

We’ve embedded a live stream below – see you back here bright and early on Thursday.