Impeachment is a means by which a government can hold a person in public office to account. Though it hasn’t been used in the UK since 1806 it is still a power that Parliament holds. Impeachment in the USA is most commonly used to refer to the removal of a president but it’s more commonly used to remove judges and government officials. There have been 4 presidential impeachment processes in America’s history: Andrew Jackson, Richard Nixon, Bill Clinton and Donald Trump.
There is some confusion about impeachment is and what impeachment means. Impeachment is undertaken by the House of Congress and acts as an indictment. This indictment is then put on trial in the Senate. The trial in the Senate is presided over by the Chief Justice of the Supreme Court. The senators act as jurors and it requires 2/3’s of the Senate to agree to remove a president. No president has ever been removed from office in this way. Nixon resigned as he was told by the Republican senators that they wouldn’t support him in the Senate trial. So presidents can be impeached but not removed as happened most recently with Bill Clinton.
The current impeachment process of Donald Trump that is underway is focused on Donald Trump withholding military aid to Ukraine in exchange for investigating Joe Biden’s son (who is on the board of the energy company in Ukraine called Burisma) and a conspiracy theory that Ukraine was responsible for the hacking of the DNC (Democrat National Convention) in 2016. The conspiracy theory goes that the Democrats engaged the Ukrainians to hack them and release their emails to “frame” the Trump campaign as conspiring with Russia. They rest this on the evidence that someone working for the DNC investigated Paul Manafort for his work in Ukraine and his questionable finances. Paul Manafort is currently serving a prison sentence for some of these crimes uncovered. The withholding of aid may have contributed to the deaths of 40+ Ukrainian soldiers who died whilst the aid was withheld while they are fighting a hot war the Eastern part of the country with Russia. The President is not cooperating with the investigation and preventing witnesses and documents from coming forward. This is viewed as obstruction and there is also evidence of obstruction documented in the Mueller Report.