A majority of the House now supports Pelosi's impeachment inquiry, reaching the magic number that could be decisive in impeaching Trump

Doug Mills-Pool/Getty Images

U.S. President Donald Trump shakes hands with Speaker of the House Nancy Pelosi while joined by Vice President Mike Pence before delivering the State of the Union address in the chamber of the U.S. House of Representatives at the U.S. Capitol Building on February 5, 2019 in Washington, DC.

• A majority of the House of Representatives - 218 members - now supports either an impeachment inquiry or the impeachment of President Donald Trump. The 218 members are all Democrats except for Rep. Justin Amash, who's an independent from Michigan.
• A simple majority vote is required to impeach a president. If this happens, the process moves on to a public trial in the Senate, where a two-thirds majority vote would be necessary to convict.
• House Speaker Nancy Pelosi announced the launch of a formal impeachment inquiry on Tuesday. This came as Trump is embroiled in a scandal linked to a whistleblower complaint from an intelligence official.
• The complaint has been tied to a July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky, in which Trump urged Zelensky to investigate former Vice President Joe Biden.
• Visit Business Insider's homepage for more stories.

There are now 218 members of Congress backing either an impeachment inquiry or the impeachment of President Donald Trump, both NBC News and Politico reported.

This is a significant threshold given it's the number of votes that would be necessary to impeach Trump in the House (a simple majority out of the 435 members). If that occurred a public trial would then take place in the Senate, which would be presided over by the Chief Justice of the Supreme Court. A two-thirds majority vote in the Senate would ultimately be necessary to convict Trump and remove him from office.

The 218 House members who support an impeachment action on some level are all Democrats except for Rep. Justin Amash, who's an independent from Michigan.

Only two presidents in US history have been impeached - Andrew Johnson and Bill Clinton - and both were acquitted in the Senate. Former President Richard Nixon famously resigned as he faced the prospect of impeachment amid the Watergate scandal.

Read more: The Trump administration just released the whistleblower complaint to Congress after a fierce tug-of-war

Given Republicans currently control the Senate, there's a low probability Trump would be removed from office if he's impeached.

House Speaker Nancy Pelosi announced the launch of a formal impeachment inquiry on Tuesday. This came as Trump is embroiled in a scandal linked to a whistleblower complaint from an intelligence official.

The complaint has been tied to a July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky. The White House released a memo on the phone call on Wednesday, which showed Trump repeatedly pressuring Zelensky to investigate former Vice President Joe Biden and his son, Hunter Biden.

Democrats have raised concerns over a potential quid pro quo in relation to $400 million in military aid that Trump moved to put the brakes on about a week before the call. Though Trump does not explicitly mention this in the call, the subject is broached by Zelensky and at one point Trump asked the Ukrainian president for a "favor." The president also mentioned that the US does "a lot for Ukraine" prior to asking him to investigate the Bidens.

Trump maintains he did nothing wrong, but the Ukraine call and whistleblower complaint now pose a serious threat to his presidency.