President Donald Trump and his congressional allies spent the first week of impeachment inquiry hearings trying to refocus the public’s attention to what they cast as the most important piece of evidence: the summary of Trump’s call to the president of Ukraine on July 25.

In the House Intelligence Committee, at press conferences and on Twitter, their message has sought to narrow the Democrats’ case to the facts of that one major event — and then attack it as insufficient to impeach the president.

It’s similar to a strategy that defense attorneys employ in bribery or corruption cases that require fitting together multiple pieces of evidence to build a picture of misconduct, former corruption prosecutors and legal experts told CQ Roll Call.

That vital piece of the puzzle doesn’t fit, the strategy goes. That big smoking gun isn’t smoking. Republicans have sought to put the July 25 call between Trump and the country’s new president, Volodymyr Zelenskiy, in the same category.

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Democrats want to paint a much broader picture. They used three witnesses Wednesday and Friday to make a case, steeped in context beyond the July 25 call itself, that Trump withheld nearly $400 million in military aid in exchange for the Ukrainian president announcing an investigation that would help Trump’s reelection.

The struggle to determine whether the public views the July 25 phone call through a narrow or wide lens emerged as a major battle line in the first week of the public phase of the Democrats’ push for impeachment — and likely will continue during public hearings next week.

Democrats on Friday called former Ambassador to Ukraine Marie Yovanovitch, known for her anti-corruption efforts over three decades in diplomatic work, to describe her sudden ouster from that position in May.

Yovanovitch, under questioning from Rep. Jim Himes, D-Conn., said that had she remained ambassador, she would not have backed Trump moves to open investigations into former Vice President Joe Biden’s son or delay military aid.

Committee Chairman Rep. Adam B. Schiff, D-Calif., said after the hearing that “it is quite clear” that Trump and his personal attorney, Rudy Giuliani, “felt it was necessary to get her out of the way.”

Witnesses not on call

But Rep. Devin Nunes of California, the panel’s top Republican, focused during the hearing on how Yovanovitch was not involved in the July 25 call or deliberations about withholding military aid.

“I’m not exactly sure what the ambassador is doing here today,” Nunes said.

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Her testimony would be better suited for a subcommittee hearing about human resources in foreign relations, Nunes said, “instead of an impeachment hearing where the ambassador is not a material fact witness to any of the accusations that are being hurled at the president for this impeachment inquiry.”

Republicans struck a similar tone two days earlier, when Democrats called two veteran diplomats whose deep knowledge of Ukraine turned into succinct explanations of the unusual circumstances of the Trump administration’s dealings with the military aid.

Rep. John Ratcliffe, R-Texas, in one of the more dramatic moments of the hearing, posed questions that framed the call as the Democrats’ entire case.

“So in this impeachment hearing today where we impeach presidents for treason or bribery or other high crimes, where is the impeachable offense in that call?” Ratcliffe said. “Are either of you here today to assert there was an impeachable offense in that call? Shout it out. Anyone?”

Although the witnesses appeared on subpoenas to answer questions and not make conclusions about impeachable offenses, Trump himself picked up on the moment to portray it as an exoneration.

Trump tweeted Thursday that Ratcliffe “asked the two ‘star’ witnesses, ‘where is the impeachable event in that call?’ Both stared straight ahead with a blank look on their face, remained silent, & were unable to answer the question. That would be the end of a case run by normal people!”

House Minority Leader Kevin McCarthy, R-Calif., at a press conference Thursday described the call summary as “still the most important piece of evidence we have.”

“And it shows no pressure or even mention of conditionality between the two leaders,” McCarthy said. “The Ukrainians did not know security assistance was under review until over a full month after the call. The full assistance was provided and no investigation was provided.”

Favor sought

Democrats have a much different view of the phone call, in which Trump tells Zelenskiy that “I would like you to do us a favor” and brings up a conspiracy theory about Ukraine’s involvement in the 2016 presidential election, along with Biden, a main rival in the 2020 election, and Biden’s son, Hunter.

The contents of that call prompted House Democrats to re-energize a flagging impeachment inquiry to focus mainly on Trump’s dealings with Ukraine.

And Democrats say there is more proof than just that phone call, such as how the military aid was released just days after the Intelligence Committee launched the probe, as Zelenskiy scheduled a CNN interview to announce investigations.

Speaker Nancy Pelosi, D-Calif., has described Trump’s dealings as bribery. And while the House impeachment inquiry is not a trial, prosecutors in corruption cases must often put a defendant’s actions in context and charges are not usually easy to prove, legal experts say.

“Bribery cases are essentially a thousand-piece puzzle,” Wayne State University law professor Peter Henning, an expert in criminal law, said. “You just put tidbits in, and pieces of the puzzle in. And then at the end you go: Here it is.”

Proving intent often elusive

Juliet Sorensen, a former federal prosecutor in Chicago, said direct evidence of intent in corruption cases can often be hard to find in something like a phone call.

“The individuals involved in the case are typically quite sophisticated people,” Sorensen said. “If they know that they’re engaging in conduct that is improper or illegal sophisticated people are not going to discuss it over the phone.”

But juries can use their common sense, said Sorensen, a law professor at Northwestern University and co-author of “Public Corruption and the Law: Cases and Materials.”

“Evidence can be considered cumulatively, a pattern of actions, of words, and activities, over time. And jurors are allowed to make reasonable inferences from the evidence,” Sorensen said. “And I think that’s what Congress should do here as well.”

While the impeachment is a political case and not a criminal one, a defense strategy in court that focuses on one piece of evidence could be effective in creating reasonable doubt, said Martha Hochberger, a professor at New York Law School and a former corruption prosecutor in New York City.

“By trying to refocus an inquiry, or just focus on a particular element and show that that element has not been proven beyond a reasonable doubt could result, probably would result in, an acquittal,” Hochberger said.