Trump repeatedly urged Ukrainian President Volodymyr Zelenskiy to work with U.S. Attorney General William Barr and with Rudy Giuliani, Trump's personal lawyer. At one point in the conversation, Trump said, "I would like for you to do us a favor."
The president's words set the parameters for the debate to come - just the fourth impeachment investigation of an American president in the nation's history. The initial response highlighted the deep divide between the two parties: Democrats said the phone call amounted to a "shakedown" of a foreign leader, while Trump - backed by the vast majority of Republicans - dismissed it as a "nothing call."
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The call is one part of a federal whistleblower complaint about the president's activities. After being stymied by the administration, lawmakers on the House and Senate intelligence committees got their first look at the complaint on Wednesday. Congress is also seeking an in-person interview with the whistleblower, who remains anonymous.
Trump spent the day meeting with world leaders at the United Nations, a remarkable TV split screen even for the turbulence of the Trump era. On his schedule: a meeting with Zelenskiy.
In light-hearted appearance before reporters, Zelenskiy said he didn't want to get involved in American election, but added: "Nobody pushed me." Trump chimed in: "In other words, no pressure."
After months of resistance, House Speaker Nancy Pelosi launched the impeachment probe on Tuesday, spurred on by the support of several moderate members in swing districts. After viewing the transcript on Wednesday, Pelosi declared: Congress must act."
Trump, who thrives on combat, has all but dared Democrats to move toward impeachment, confident that the specter of an investigation led by the opposition party will bolster rather than diminish his political support.
"It's a joke. Impeachment, for that?" Trump said during a news conference in New York. He revived the same language he has used for months to deride the now-finished special counsel investigation into election interference, declaring impeachment "a hoax" and the "single greatest witch hunt in American history."
Republicans largely stood by the president and dismissed the notion that the rough transcript revealed any wrongdoing by Trump.
"I think it was a perfectly appropriate phone call, it was a congratulatory phone call," said Rep. Liz Cheney, the No. 3 House Republican. "The Democrats continually make these huge claims and allegations about President Trump, and then you find out there's no there there."
The memo released by the White House was not a verbatim transcript, but was instead based on the records of officials who listened to the call. The conversation took place on July 25, one day after special counsel Robert Mueller testified on Capitol Hill about his investigation into Russia's 2016 election interference.
In the 30-minute phone call with Zelenskiy, Trump encourages the Ukrainian leader to talk with Giuliani and Barr about Biden and his son Hunter, who served on the board of a Ukrainian gas company. Trump, immediately after saying he and Zelenskiy would be in touch, references Ukraine's economy, saying: "Your economy is going to get better and better I predict. You have a lot of assets. It's a great country."
At another point in the conversation, Trump asks Zelenskiy for a favor: his help looking into a cybersecurity firm that investigated the 2016 hack of the Democratic National Committee and determined it was carried out by Russia. Trump has falsely suggested Crowdstrike was owned by a Ukrainian.
In the days before the call with Zelenskiy, Trump had ordered the freezing of $400 million in military aid for Ukraine - prompting speculation that he was holding out the money as leverage for information on the Bidens. Trump has denied that charge and the aid package does not come up in the conversation.
Trump has sought to implicate Biden and his son in the kind of corruption that has long plagued Ukraine. Hunter Biden served on the board of a Ukrainian gas company at the same time his father was leading the Obama administration's diplomatic dealings with Kyiv. Though the timing raised concerns among anti-corruption advocates, there has been no evidence of wrongdoing by either the former vice president or his son.
Biden said it was "tragedy" that Trump was willing to "put personal politics above his sacred oath." He singled out Trump's attempts to pull Barr and the Justice Department into efforts to investigate Biden, calling it "a direct attack on the core independence of that department, an independence essential to the rule of law."
While the possibility of impeachment has hung over Trump for many months, the likelihood of a probe had faded after special counsel Robert Mueller's Trump-Russia investigation ended without a clear directive for lawmakers.
Since then, the House committees have revisited aspects of the Mueller probe while also launching new inquiries into Trump's businesses and various administration scandals that all seemed likely to drag on for months.
Details of Trump's dealings with Ukraine prompted Democrats to quickly shift course. By the time Pelosi announced the probe, about two-thirds of House Democrats had announced they were moving toward impeachment probes.
The burden will probably now shift to Democrats to make the case to a scandal-weary public. In a highly polarized Congress, an impeachment inquiry could simply showcase how clearly two sides can disagree when shown the same evidence rather than approach consensus.