23 photos show the key moments of Trump's impeachment so far

On September 24, House Speaker Nancy Pelosi announced Congress was launching an impeachment inquiry to look into an anonymous complaint that accused President Donald Trump of pressuring Ukrainian President Volodymyr Zelensky. She said Trump's actions had betrayed his oath as president, national security, and the integrity of US elections.

Source: PRI

Trump was accused of withholding $400 million in military aid unless Ukraine investigated former Vice President Joe Biden and his son Hunter for corruption. The two leaders happened to meet at the UN on September 25.

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That same day, the White House released a memo detailing the call. It showed Trump told Zelensky the US did "a lot for Ukraine," and the phrase, "I would like you to do us a favor though."

The impeachment inquiry began behind closed doors, much to Republicans' chagrin. Democrats said they began with confidential testimonies to maintain the integrity of the investigation. Explosive information still leaked out, though.

Sources: PRI, Business Insider, The New York Times

On October 23, tensions boiled over, when a group of 30 Republicans stormed a closed-door meeting, and delayed testimony by five hours over safety concerns.

Sources: Washington Post, Business Insider

On October 31, the House of Representatives voted 232-196 in favor of formalizing the impeachment inquiry. This meant the next stage of the proceedings would be outlined, and included the plan to make the hearings public. Trump tweeted that it was "The Greatest Witch Hunt in American History."

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On November 13, the hearings went public. This raised the stakes. When former President Richard Nixon's impeachment was televised, 80% of America tuned in for at least some of the hearing.

Sources: PRI, The New York Times

By televising the hearings, the Democrats were giving the public a direct look at the key figures, the process, and the allegations, hoping it would sway the public to support impeaching the president.

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Rep. Adam Schiff heads the House Intelligence Committee and is playing a key role in the proceedings. The Washington Post described his methodical approach as bringing a "prosecutor's sensibility" to the role, by staying calm and refusing to be baited.

Sources: The Atlantic, The Washington Post

The public hearings began with Bill Taylor, the acting US ambassador to Ukraine. Taylor confirmed the quid pro quo between Trump and Ukraine, and said in his entire career, spanning decades, he had never seen a president do as Trump had done.

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George Kent, a deputy assistant secretary for Europe and Eurasian affairs, gave his testimony alongside Taylor. It focused on former New York Mayor Rudy Giuliani's attempts to get information about the Bidens from Ukraine. He clarified that it was a personal mission of Giuliani's to get the damaging information, and not US foreign policy.

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Kent also drew attention for his yellow and blue bow tie, and his 48-ounce Nalgene water bottle.

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Republicans used a variety of defenses to confuse and distract during the hearings, including characterizing Taylor and Kent's testimonies (which were given under oath) as inaccurate hearsay.

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Another tactic was calling for the anonymous whistleblower to publicly testify. Rep. Jim Jordan of Ohio, one of the most vocal Republicans during the hearings, said it was a sad day for the country that they would never get a chance to question the whistleblower, whom he described, despite not knowing the person's identity, as biased against Trump.

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Democratic Rep. Peter Welch of Vermont shot back and said, "I say to my colleague, I'd be glad to have the person who started it all come in and testify — President Trump is welcome to take a seat right there." His response was greeted with laughter.

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Former US Ambassador Marie Yovanovitch testified on November 15. She said she was removed from her post because she got in the way of efforts by the Trump administration to get Ukraine to investigate the Bidens. But while Trump said he had lost confidence in her, she said she'd done nothing wrong, and called her ouster a "smear campaign."

Sources: The Wall Street Journal, PRI

Daniel Goldman, director of investigations for the House Intelligence Committee, was a key interviewer during the hearings, and got the most from Yovanovitch.

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He asked her two key questions — had she, in her 33 years as a foreign-service officer, ever had concerns about her job performance, and had she heard of a US president recalling an ambassador based on false allegations. To both she answered, "no."

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Trump's past and current tweets played a part in the proceedings. As Trump attacked her in real time on Twitter, saying everywhere she went "turned bad," Yovanovitch was asked how she felt about the tweets.

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She told the committee it was "very intimidating," to be publicly smeared. Experts told Business Insider's Eliza Relman that the tweets amounted to witness intimidation.

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Like Kent, Yovanovitch stayed hydrated in her nearly seven hours of testimony.

When Yovanovitch finished her testimony, the audience and some members of Congress broke into applause, which is highly unusual.

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At least nine more testimonies are to come, including Vice President Mike Pence's adviser Jennifer Williams, Lt. Col. Alexander Vindman, former US special representative to Ukraine Kurt Volker, and former NSC staffer Tim Morrison.

Source: Business Insider