WASHINGTON: Starting with Donald Trump's phone call to the leader of Ukraine, and ending with his acquittal on Wednesday, here is a look back at key moments in the impeachment of the 45th US president:
- July 25: Trump-Zelensky call -
A few days after Trump -- without explanation -- suspended hundreds of millions of dollars in military assistance to Ukraine, the US leader holds a 30-minute telephone conversation with the country's new president Volodymyr Zelensky.
Asking Zelensky to "do us a favor," the president presses him to investigate Joe Biden, his potential Democratic rival in the 2020 election, as well as Biden's son, Hunter -- who served on the board of a Ukrainian gas company accused of corrupt practices.
The aid is eventually released by the White House on September 11 -- after the freeze is made public.
- August 12: Whistleblower complaint filed -
Less than three weeks later, an anonymous whistleblower in the US intelligence community files an internal complaint about the Trump-Zelensky call, describing it as a matter of "urgent concern."
The complaint is deemed "credible" by Michael Atkinson, inspector general for the intelligence community, who later informs Congress of its existence without revealing its contents.
- September 24: Impeachment inquiry -
The Democrats, who control the House of Representatives, announced the opening of an impeachment inquiry into the Republican president, for abuse of power.
The following day, the White House releases a rough transcript of Trump's call with Zelensky, which confirms the president repeatedly asked him to probe the Bidens and to "look into" the matter with both Rudy Giuliani, his personal lawyer, and Attorney General Bill Barr.
That comes hours before the two leaders meet in New York, where Zelensky denies he was pressured by Trump.
The day after that, on September 26, the whistleblower complaint is released. It accuses Trump of "using the power of his office to solicit interference from a foreign country in the 2020 US election."
Trump rejects the House inquiry as a "witch hunt."
- November 13-21: Public hearings -
After closed-door testimony by witnesses in October, the House Intelligence Committee begins public hearings.
Those testifying in the marathon televised sessions include top envoy to Ukraine William Taylor, former ambassador to Ukraine Marie Yovanovitch and National Security Council member Lieutenant Colonel Alexander Vindman.
The biggest bombshell comes from Gordon Sondland, the US envoy to the European Union and a Trump ally, who tells lawmakers he followed the president's orders in seeking a "quid pro quo" deal with Ukraine.
But Sondland also acknowledges that, while he concluded there was a link between the aid freeze and the investigations sought by Trump, the president did not tell him so explicitly.
- December 18: Trump impeached -
After the House inquiry finds "overwhelming" evidence of misconduct, Trump is impeached for abuse of power and obstruction of Congress -- setting up a Senate trial on removing him from office.
The vote makes Trump just the third president in US history to be impeached.
- January 21: Trump trial begins -
Trump's impeachment trial opens with 100 senators -- 53 Republican and 47 Democrats -- sitting in silence as the Democratic prosecution team, followed by Trump's defense, argue for and against his removal from office.
Over two weeks of marathon hearings, Democrats make the case that acquitting Trump of abuse of power charges would amount to the "normalization of lawlessness."
Trump's defense team counters that the impeachment is politically driven, that Trump did not tie Ukraine aid to investigations -- and that his actions were not impeachable because he believed his re-election was in the public interest.
- February 5: Trump acquitted -
The US Senate acquits Trump of both charges, almost entirely along party lines.
Senators clear the president by 52 votes to 48 on the abuse of power article and 53 to 47 on the obstruction charge -- falling far short of the two-thirds supermajority required for conviction.
One Republican, Utah Senator Mitt Romney, a longtime Trump foe, risks the ire of the White House to vote alongside Democrats on the first count, saying Trump was "guilty of an appalling abuse of public trust."