One of the most important issues in President Trump's impeachment defense is also one of the least explored: To what degree were Trump's concerns about Ukraine valid? It's well documented that the president fixated on Ukrainian activity in the 2016 election and on the Bidens' actions in the Burisma matter. Democrats and many in the media dismiss his concerns as "conspiracy theories." But to what extent were those concerns, in fact, legitimate?

If they were even mostly legitimate, then Trump defenders could say: "Look, he had a point. Even if one thinks he handled the issue inappropriately, the fact is, what was going on in Ukraine was worrisome enough for a United States president to take notice." That would not change minds among those dead set on impeachment, but among others, it would make the case for impeachment and removal much harder to make.

Of Trump's two concerns — 2016 interference and Biden/Burisma — the 2016 part came first and is the foundation for Trump's later concerns about the former vice president. So leave the Biden part for a later article and focus on Ukraine and the 2016 election. Republicans insist Ukraine did, in fact, try to interfere in the American political process in 2016, and they point to five examples:

1) Government ministers attack. During the summer of 2016, candidate Trump was under constant criticism for being insufficiently critical of Russian President Vladimir Putin. At the end of July, Trump stirred up a controversy when, during an appearance on ABC, he insisted that Putin would not invade Ukraine under a Trump presidency. "He's not going into Ukraine, OK," Trump said. "Just so you understand — he's not going to go into Ukraine, all right?" But seconds later, Trump suggested he might, as president, give U.S. recognition to Russia's illegal annexation of Crimea. "I'm going to take a look at it," Trump said. "But you know, the people of Crimea, from what I've heard, would rather be with Russia than where they were. And you have to look at that, also."

A few days later, at a campaign rally, Trump said of Crimea, "You want to have World War III to get it back?"

From Ukraine's perspective, Trump's Crimea statements were linked to the presence of Paul Manafort in the Trump campaign. First hired in March 2016 to organize delegate support, Manafort was promoted to campaign chairman in June. Few Americans knew much about Manafort, whose best-known political efforts were with the Gerald Ford campaign in 1976. But Manafort later made millions in Ukraine working for President Viktor Yanukovych and the pro-Russia Party of Regions. The corrupt Yanukovych was ousted in 2014 in what Ukrainians call the "Revolution of Dignity." After that, when anti-Yanukovych Ukrainians looked at Trump, they saw the hand of Manafort, and of Russia.

Trump's comments on Crimea set off a strong reaction in Ukraine. Some high-ranking members of the Ukrainian government took to social media in an attempt to influence, as best they could, the U.S. presidential race. Arsen Avakov, at that time the interior minister, tweeted that Trump was a "clown" and added that the Republican candidate was "an even bigger danger to the U.S. than terrorism."

On Facebook, Avakov wrote, according to a BBC translation: "The shameless statement of U.S. presidential candidate Trump on the possible recognition of Crimea as Russia is a diagnosis of a dangerous outcast ... He is dangerous both for Ukraine and the U.S., to the same extent. An outcast bowing down to Putin's dictatorship cannot be the guarantor of democratic freedoms in the U.S. and the world."

Avakov suggested Manafort was responsible for Trump's position. "Where will Manafort take Trump?" Avakov asked. He completed the post by adding a photo of a mural in Vilnius portraying Trump and Putin in a passionate kiss — a popular picture in Resistance circles worldwide.

At about the same time, a former prime minister, Arseny Yatseniuk, made the case that Trump's statement on Crimea and Putin made his campaign fair game for Ukrainians. Trump's comments "go beyond any form of domestic political campaigning," Yatseniuk wrote on Facebook. "An official candidate for the United States presidential election has challenged the very values of the free world, civilized world order and international law."

"What Donald Trump said about Crimea today, he might tomorrow extend to some other part of the world," Yatseniuk continued, "in Europe, Asia, or the Americas. And that makes it worrisome for everyone."

2) The ambassador takes a position. At about the same time as a government minister and a former top official were taking to social media, Ukraine's ambassador to the U.S., Valeriy Chaly, wrote an op-ed that was published in the Hill. Using much more temperate language than Avakov and Yatseniuk, Chaly said that Trump's statements on Crimea have "raised serious concerns in Kyiv and beyond Ukraine." Trump's words "stand in sharp contrast to the Republican party platform," Chaly continued, as well as against "bipartisan support" for U.S. sanctions against Russia.

Chaly did not call Trump a "clown" or use any terms of derision. But, as Ukraine's ambassador, he was surely speaking in an official capacity — that is, as a representative of the Ukrainian government. The op-ed was a clear message, from a high-ranking Ukrainian government official, to the Trump campaign and American voters.

3) Leshchenko and the black ledger. Serhiy Leshchenko is well known in Ukraine as a journalist, crusader against corruption, and a member of Parliament. In August 2016, a few weeks after Trump's statements about Crimea, Leshchenko took on a new task. On Aug. 28, the Financial Times published a story, "Ukraine's leaders campaign against 'pro-Putin' Trump," which began:

For years, Serhiy Leshchenko, a top Ukrainian anti-corruption campaigner, worked to expose kleptocracy under former president Viktor Yanukovich. Now, he is focusing on a new perceived pro-Russian threat to Ukraine: U.S. presidential candidate Donald Trump.

The story went on to recount how Leshchenko, working with Ukraine's anti-corruption bureau, published the "black ledger," which was purported to be a document listing secret cash payments to, among others, Manafort, during the Yanukovych regime. When the New York Times published a front-page story on the ledger: "Secret Ledger in Ukraine Lists Cash for Donald Trump's Campaign Chief," the ensuing controversy forced Manafort to resign.

Leshchenko, speaking from Ukraine, made no secret of his desire to tip the U.S. presidential election. "A Trump presidency would change the pro-Ukrainian agenda in American foreign policy," Leshchenko told the Financial Times. "For me it was important to show not only the corruption aspect, but that [Trump is a] pro-Russian candidate who can break the geopolitical balance in the world."

Some gave Leshchenko and his allies credit for helping shape the U.S. election. "Ukraine's anti-corruption activists have probably saved the Western world," a professor studying Ukraine and Russia told the Financial Times.

The only problem was that the black ledger may or may not have been legitimate. There's no doubt that Manafort received payments from Ukraine. He was convicted on charges of not paying taxes on millions of dollars in income from that country. But there is also no doubt that in all of Manafort's legal proceedings with Trump-Russia special counsel Robert Mueller, the black ledger was never cited as evidence. "It is true that some aspects of the 'black ledger' story remain unclear," the Washington Post wrote recently. "Questions about the origins and authenticity of the documents persist; as Post reporters noted, Mueller's office didn't introduce the ledger at Manafort's trial."

But the ledger was definitive proof of one thing: the determination of Ukraine's political and activist establishment to exert influence over the 2016 U.S. presidential election. The Financial Times article ended with this: "It was a consensus view, Leshchenko suggested to the Financial Times, telling the paper that the majority of Ukraine's politicians 'are on Hillary Clinton's side.'"

4) Leshchenko, Nellie Ohr, and Fusion GPS. Leshchenko did not confine his efforts to the black ledger. His name also came up when House Republicans looked into the origins of the Trump-Russia investigation. During the campaign, Leshchenko was apparently providing information — no word on whether it was accurate or not — to Fusion GPS, the opposition firm that worked on anti-Trump projects under contract with a law firm representing the Democratic Party and the Clinton campaign. Fusion GPS, of course, commissioned the notorious Steele dossier that contained a variety of sensational, salacious, and never-proven allegations about Trump.

It turns out one of Fusion GPS' sources was Leshchenko. During the Fusion GPS anti-Trump effort, information from Leshchenko ended up in the hands of Fusion GPS employee Nellie Ohr, the wife of senior Justice Department official Bruce Ohr.

In an October 2018 interview with Republican lawmakers, Nellie Ohr was asked about her work doing research into two of the president's family members, son Donald Trump Jr. and daughter Ivanka Trump. "What were you trying to find with regard to each of these individuals?" asked GOP lawyer Ryan Breitenbach. "What was the purpose of looking into the family members?"

"To see whether they were involved in dealings and transactions with people who had suspicious pasts, or suspicious types of dealings," Ohr answered.

Breitenbach asked whether Ohr got information from sources connected to her fellow Fusion GPS officials Glenn Simpson and Jake Berkowitz. "Was any research based off of sources of theirs that you were aware of?"

"Yes," said Ohr.

"And who were the sources?"

"I recall they were mentioning someone named Serhiy Leshchenko, a Ukrainian," Ohr said.

"Were you aware of how they had a connection with him?" Breitenbach asked.

"I am not aware."

"But you were aware that he was a source of information that was leading to information that they had, that they were then presenting to you as reasons for following up on opposition research or what research — "

"Yes," said Ohr.

" — that is, on President Trump or his family?"

"Yes," said Ohr.

A few moments later, Ohr was asked whether she had been given "a tip that was based off of a source that was a Ukrainian source, Serhiy Leshchenko. Is that right?"

"Yes," Ohr said. "They were giving me some information that had originated with [Leshchenko] in some way."

5) The mysterious Alexandra Chalupa. The Trump-Ukraine brouhaha has shed light on the activities of a woman named Alexandra Chalupa, who worked in the Clinton White House and later with the Democratic National Committee. Chalupa's parents emigrated to the U.S. from Ukraine and she "maintains strong ties to the Ukrainian-American diaspora and the U.S. Embassy in Ukraine," according to a January 2017 article in Politico, "Ukrainian efforts to sabotage Trump backfire," that is the best source of information on her activities.

Politico reported that in 2014, Chalupa had a client "interested in the Ukrainian crisis." As part of that, she began looking into Manafort's activities in Ukraine. Chalupa "developed a network of sources in Kiev and Washington, including investigative journalists, government officials and private intelligence operatives." In 2015, when Trump was leading the Republican presidential nominating contest, Chalupa began focusing her research on him, Politico said.

The website reported Chalupa "occasionally shared her findings with officials from the DNC and Clinton's campaign." In March 2016, she went to the Ukrainian Embassy in Washington and "shared her concern," according to Politico, with Ambassador Chaly and one of his deputies, Oksana Shulyar. Not long after, Chalupa spoke again with the DNC, and, according to Politico, "with the DNC's encouragement, Chalupa asked embassy staff to try to arrange an interview in which [then-President Petro] Poroshenko might discuss Manafort's ties to Yanukovych."

The embassy said no but was "helpful," according to Chalupa. Politico then added this:

Andrii Telizhenko, who worked as a political officer in the Ukrainian Embassy under Shulyar, said she instructed him to help Chalupa research connections between Trump, Manafort and Russia. "Oksana said that if I had any information, or knew other people who did, then I should contact Chalupa," recalled Telizhenko, who is now a political consultant in Kiev. "They were coordinating an investigation with the Hillary team on Paul Manafort with Alexandra Chalupa," he said, adding "Oksana was keeping it all quiet," but "the embassy worked very closely with" Chalupa. In fact, sources familiar with the effort say that Shulyar specifically called Telizhenko into a meeting with Chalupa to provide an update on an American media outlet's ongoing investigation into Manafort.

Politico also reported that Chalupa "discussed the possibility of a congressional investigation with a foreign policy legislative assistant in the office of Rep. Marcy Kaptur, who co-chairs the Congressional Ukrainian Caucus." The investigation did not happen.

So, what does it all add up to? There is certainly enough evidence for someone — say, the president of the U.S. — to conclude that, as Leshchenko said, the majority of Ukrainian politicians were on Clinton's side and were willing to try to influence an American election. No, there is not evidence of "CrowdStrike" or the server that Trump mentioned in his July 25 call with new Ukrainian President Zelensky. But there is plenty of evidence of Ukrainian efforts to influence the election.

One striking aspect of the Democratic impeachment hearings on Capitol Hill is the number of witnesses, U.S. diplomats and experts on Ukraine, who either knew little about the Ukrainians' anti-Trump activities or dismissed them as no big deal. Recalled U.S. Ambassador Marie Yovanovitch, for example, referred to them as "isolated incidents." Her position seemed to be that if the Ukrainian interference was not as big as Russian interference, and it certainly wasn't, then there was no problem.

A more extreme version of that opinion has appeared many times in the press. On Tuesday, CNN's Jim Sciutto tweeted, "Be aware: the ranking Republican on House Intel @DevinNunes is repeating a baseless conspiracy theory that Ukraine, not Russia, interfered in the 2016 election. This is false and — notably — a Kremlin talking point." Many others in the media and the Democratic Party said similar things.

But that opinion is based on the premise that either Russia or Ukraine interfered. It could not have been both. And the critics, like Sciutto, appeared to suggest that Republicans, echoing the Kremlin, are somehow denying the fact of Russian interference. They should read Devin Nunes' committee's 2018 report on Russian interference entitled, "Report on Russian Active Measures."

In reality, what Republicans were saying is that it appears that both Russia and Ukraine interfered, although not on the same scale. "Certainly more than one country can be trying to influence our elections, would you agree with that?" Republican Rep. Brad Wenstrup asked former U.S. envoy to Ukraine Kurt Volker Tuesday.

"I agree with that," Volker said.

"In the president's mind, he did think Ukraine was trying to influence the 2016 election," added Republican Rep. Jim Jordan. "Democrats want to deny it, but things happened." Jordan went on to list the actions of Avakov, Leshchenko, Chaly, and others. "That probably sticks in a candidate's mind," he said.

Indeed it did. In the course of events currently under investigation, Volker recalled, the president said Ukraine "tried to take me down." He wasn't wrong.

