The GOP's own witnesses blew up their case and a Purple Heart recipient was accused of disloyalty. Here are the biggest takeaways from Tuesday's impeachment hearings.

• The second week of impeachment hearings began as four officials gave testimony showing how President Donald Trump tried to strongarm Ukraine into delivering politically motivated investigations.
• Lt. Col. Alexander Vindman, the top Ukraine expert on the National Security Council, and Jennifer Williams, a State Department official, offered firsthand accounts of Trump's "inappropriate" and "unusual" July 25 phone call with Ukraine's president.
• Vindman, an immigrant and Purple Heart recipient, gave an emotional opening statement highlighting his sense of duty and love of country while fielding Republican attacks on his patriotism.
• Kurt Volker, the US's former envoy in Ukraine, and Tim Morrison, a former NSC official, blew a hole through many of Trump's defenses in the impeachment inquiry.
• The top Republican on the House Intelligence Committee made a telling Freudian slip indicating just how badly the hearing went for the GOP.
• Scroll down to read the biggest takeaways from Tuesday's marathon testimony.
• Visit Business Insider's homepage for more stories.

Four officials publicly testified in public impeachment inquiry hearings on Tuesday and added to an emerging picture of how President Donald Trump tried to strongarm Ukraine into launching politically motivated investigations while withholding military aid and a White House meeting from Ukraine's president.

The officials who testified on Tuesday are:

• Lt. Col. Alexander Vindman, the top Ukraine expert on the National Security Council.
• Jennifer Williams, a foreign service aide detailed to Vice President Mike Pence.
• Tim Morrison, the NSC's former official in charge of overseeing Russia and Europe policy.
• Kurt Volker, the US's former Special Representative to Ukraine.

Vindman and Williams testified together beginning at 9 a.m. ET, and Volker and Morrison jointly testified beginning at 3:30 p.m.

Here are the biggest takeaways from Tuesday's hearings:

• Vindman sent an emotional message to his dad.
  • "Dad, my sitting here today, in the US Capitol talking to our elected officials is proof that you made the right decision forty years ago to leave the Soviet Union and come here to United State of America in search of a better life for our family," Vindman testified. "Do not worry, I will be fine for telling the truth."
  • He also drew a stark comparison to Russia, where Vindman said "my act of expressing my concerns to the chain of command in an official and private channel would have severe personal and professional repercussions, and offering public testimony involving the president would surely cost me my life."
• Vindman's hands were shaking at times as he read from his opening statement, and he often halted while speaking. The delivery was a reminder of how the impeachment inquiry has thrust government officials and career foreign service officers - most of whom rarely speak publicly - into the spotlight.
  • "I never thought I would be sitting here testifying in front of this committee and the American public, about my actions. When I reported my concerns, my only thought was to act properly and to carry out my duty," he said.

Republicans tried to call a decorated war veteran's loyalty to the US into question, without any evidence

• Republicans made baseless and absurd allegations to sow doubts about Vindman's loyalty to the US.
  • Vindman's family fled the Soviet Union and arrived in the US as refugees. He and his brothers have dedicated themselves to public service. In addition to serving on the National Security Council, Vindman served in the military and was awarded the Purple Heart after being injured in Iraq in 2004.
  • Steve Castor, the minority council, embarked on a bizarre line of questioning that seemed to imply that because Vindman was offered the position of defense minister in Ukraine, he had a dual loyalty to Ukraine.
  • But the former army officer shot Castor down: "I'm an American. I came here when I was a toddler and I immediately dismissed these offers. I did not entertain them."
• Williams and Vindman - both of whom were participants in a July 25 call in which Trump pressured Ukrainian President Volodymyr Zelensky to deliver politically motivated investigations - testified that they believed the call was "inappropriate" and "unusual."
  • These statements were significant: they are firsthand accounts of a phone call that directly undercut Trump's claim that the conversation was "perfect."
• The room broke into applause as Vindman testified about his patriotism and sense of duty.
  • Democratic Rep. Sean Patrick Maloney of New York asked Vindman why he had "confidence that you can do that and tell your dad not to worry."
  • "Congressman, because this is America," Vindman said. "It is the country that I have served and defended and all of my brothers have served, and here, right matters."

John Bolton wasn't there, but he featured prominently in the hearing

• Former national security adviser John Bolton featured prominently in the hearing despite the fact that he's refused to testify while waiting on a judge to rule if he should comply with Congress' subpoena.
  • Bolton was at the center of a few key interactions at the heart of the impeachment inquiry, and his lawyer dropped a tantalizing hint in a letter that indicated Bolton has more inside knowledge than has been publicly confirmed.
• The White House attacked Vindman while he was testifying, and Williams responded to Trump's public criticisms of her on Twitter.
  • Trump's attacks on the officials testifying in the impeachment inquiry have drawn sustained backlash and allegations of attempted witness intimidation.
• Volker dramatically altered his public testimony on Tuesday from what he said behind closed doors.
  • When he first testified, Volker categorically denied that any investigations into former Vice President Joe Biden, Burisma Holdings, or the 2016 election were raised during a July 10 White House meeting with Ukrainian officials.
  • On Tuesday, Volker acknowledged that Gordon Sondland, the US ambassador to the EU, brought up the investigations and that he found it "inappropriate."
• In a Freudian slip, GOP Rep. Devin Nunes referred to Volker and Morrison as "your witnesses" while speaking to Democrats. But both men were on the GOP witness list.
  • Nunes' flub is a telling sign of how badly the impeachment hearing went for Republicans, as their own witnesses undermined their defense of the president.
  • They testified about their discomfort with Giuliani's involvement in the Ukraine pressure campaign as Trump's personal lawyer. They also testified about the unusual nature of Trump's request that Ukraine investigate Burisma Holdings.
  • Morrison told lawmakers that Trump's reference to CrowdStrike and an alleged hidden DNC server weren't part of the list of talking points for the July phone call. "I was hoping for a more full-throated support for President Zelensky's reform agenda," he said.
  • He also told them investigating the Bidens "was not a policy objective," blowing up Trump's insistence that he had no personal stake in pressuring Zelensky for investigations.
  • Volker said he now understands the Burisma investigation was directly linked to Biden.

• Read more of Insider's impeachment coverage:
• Think Trump will get impeached? Gambling sites say the odds are in your favor
• Trump could be impeached and removed from office but still win reelection in 2020
• Over half of the House of Representatives support the impeachment inquiry against Trump - see all of them here
• Everything you need to know about Trump's impeachment process: What's happened, who the players are, and what comes next

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