After US President Donald Trump had a controversial telephone conversation with the President of Ukraine in July, it will now be formally investigated whether Trump can be deposed. It seems to be a breakthrough, but what are the concrete consequences and how did we get here?

1. What is the matter?

Impeachment is the procedure by which a US president can be deposed. The possibility has been a discussion within the opposition for months, but until recently, Nancy Pelosi, the Democratic President of the House of Representatives, did not want to know about it.

On Tuesday evening (Dutch time) this changed suddenly: Pelosi announced to start a formal investigation into the possibility of deposition.

2. Why is deposition being investigated right now?

This is due to two revelations. On July 25, Trump allegedly put pressure on his Ukrainian counterpart by telephone. According to various sources, he asked Volodimir Zelensky "eight times" to investigate the son of former vice president Joe Biden. Biden is Trumps potential political opponent in the 2020 presidential election. This revelation came from a whistleblower within the US intelligence service.

Trump claims that in 2016, Joe Biden called on Ukraine to dismiss the head of justice, which would have once investigated the gas company of Bidens son Hunter.

Later, Trump also appeared to have given the order to temporarily withhold millions of dollars in financial support for Ukraine, just a week before the phone call with Zelensky.

3. What exactly is so controversial about that telephone conversation?

According to the opposition, the revelations are evidence that Trump was trying to force an investigation into Zelensky. The Democrats state that if this is true, Trump is abusing his presidential position for his own political gain. He then actually engages a foreign power to influence the US presidential election.

Trump, in turn, calls the allegations "the biggest witch hunt" and denies that there is any influence. He promised to publish the complete transcript of the telephone conversations with Zelensky on Wednesday.

4. What is happening now?

Six congressmen are now investigating, according to Pelosi, whether Trump may have done something that would allow a removal procedure. They already did, but when they find something, they can present it to the House of Representatives, who will hold a vote on it. Then the Senate still has to approve it.

5. What is the chance that it will succeed?

The Democrats have a majority in the House of Representatives. Here there is a considerable chance that an impeachment will be approved. However, once the House has agreed, this does not mean that Trump can be deposed. Then the Senate still has to agree to a two-thirds majority, the equivalent of our Senate. Since the Republicans have the majority in the Senate, this seems impossible.