President Donald Trump is facing a legal process that could see him removed from office. His opponents have been calling for an investigation into his decisions and behaviour since he was sworn in. They allege that he’s repeatedly lied and taken part in dodgy dealings but now the Democrats have launched an impeachment inquiry amid accusations Trump violated the US constitution.

What is impeachment?

Impeachment is the process of removing a government official from office. An inquiry investigates if their conduct falls under Article Two of the US Constitution: “Treason, bribery, or other high crimes and misdemeanours”.

Essentially the president will be on trial in the rare proceedings.

Only three presidents have faced impeachment – Andrew Johnson, Richard Nixon and Bill Clinton.

How does impeachment work?

The process is started by the House of Representatives, and only needs a simple majority to pass.

If this happens, the trial will then be held in the Senate where senators will act like a jury to decide whether or not the president is guilty. Two-thirds of senators must vote in favour of impeaching the president in order to remove him from the job.

Why is Trump being impeached?

President Trump is accused of pressuring Ukraine’s president Volodymyr Zelensky by holding back aid unless he dug up damaging information on his Democrat opponent Joe Biden and his son Hunter.

Hunter Biden worked for a Ukrainian company when his father was US vice-president.

The investigation was triggered by a whistleblower concerned about a phone call between Trump and Zelensky, who accused the president of abusing his power in order to interfere in the 2020 election.

What evidence is there?

A transcript of the call revealed that Trump had urged President Zelensky to investigate allegations against Joe and Hunter Biden.

The call came after Trump blocked millions of dollars of military aid to Ukraine. The White House denies that the president made it clear that the release of the aid was dependent on Mr Biden being investigated.

Why did Trump want Biden to be investigated?

Trump and his allies have suggested that during his time as Vice-President Joe Biden wanted Ukraine’s then-prosecutor general,Viktor Shokin, fired because he was investigated the gas company his son worked for, Burisma.

It wasn’t just Mr Biden who called for the removal of Mr Shokin, who was criticised for failing to tackle corruption – he was backed by the International Monetary Fund and other European allies.Both Bidens have denied any wrongdoing.

Could Trump really be removed?

Conventional wisdom says not but some pundits think he could. Around 20 Republican senators would have to vote against him for him to be ousted but he is known to be disliked among his congressional ranks. He’s likely to be impeached by the Democrat-heavy house but unlikely to be convicted by the Senate.