Like Gore was to Clinton, the former Indiana governor has been a stalwart ally to the man who put him in power. The day the White House released a transcript of Trump’s July 25 call with Ukrainian President Volodymyr Zelensky, in which he urged Zelensky to “look into” unsubstantiated claims against Joe Biden and his youngest son, Pence declared on Fox Business that Trump “did nothing wrong” and only “spoke about issues that were appropriate” with the Ukrainian leader.

As House managers were delivering the two articles of impeachment against Trump on Thursday, Pence continued his defense of Trump in the pages of The Wall Street Journal. Recalling then-Sen. Edmund Ross’ critical decision to buck his party and vote against President Andrew Johnson’s impeachment in 1868, the vice president suggested Senate Democrats should “stand up to the passions of their party” and oppose conviction. (A historian who recently published a book about the Johnson trial says the Ross analogy is far off the mark, noting that the Kansas senator engaged in a “quid pro quo” in exchange for his vote favoring the president’s acquittal).

Then there is the uniquely Trumpian reason that Pence can’t been seen as eyeing the Oval Office — the president demands unquestioning loyalty from his subordinates.

“I can’t imagine anything that would drive Trump more crazy than watching his VP scheme openly behind his back, so expect him to go out of his way to defend the president as much as possible,” said a former White House official, noting that Pence remained above the fray even when Trump tried to distance himself from the Ukraine controversy by suggesting reporters question his vice president instead.

“I think you should ask for Vice President Pence’s conversations, because he had a couple conversations also,” Trump said during a late September news conference on the sidelines of the United Nations General Assembly in New York.

Pence claimed in October that he was working with White House attorneys to release the transcripts of his phone calls with Zelensky, but none of them have yet been made public.

Still, the vice president has been sucked into the impeachment scandal in other ways. Last May, Pence canceled plans to attend Zelensky’s inauguration, resulting in a three-person delegation led by then-Energy Secretary Rick Perry to go in his place. The decision to pull Pence from the trip to Kiev came directly from Trump, according to Jennifer Williams, a top Pence national security aide who testified about the matter last November to House impeachment investigators. She added that she never received an explanation for the reversal.

Additional details about Pence’s knowledge of the administration’s pressure campaign on Ukraine came to light last week when Lev Parnas, an associate of Trump’s personal attorney, Rudy Giuliani, sat for an interview with MSNBC’s Rachel Maddow. The Soviet-born businessman, who helped Giuliani navigate his way through the Ukraine political world, explained that the decision to not send Pence to Zelensky’s swearing-in came after the incoming administration made it clear they wouldn’t be opening an investigation into Biden, a top 2020 Democratic presidential contender.

“I remember Rudy going, ‘OK, they’ll see,’” Parnas said. “And basically, the next day … to my awareness, Trump called up and said to make sure Pence doesn’t go there.”

In September, when the president called off travel plans to Poland that included an expected meeting with Zelensky, he sent Pence in his place. After Pence met with the Ukrainian leader, he was asked whether the two discussed Biden. The vice president replied only that the conversation covered U.S. financial support for the Eastern European country and “corruption.”

Parnas later claimed that Pence “couldn't have not known” when he met with Zelensky that the withholding of U.S. aid to Ukraine was linked to the country’s refusal to announce investigations into Trump’s rivals.

Pence and Parnas were photographed together as part of a group that included Trump and Giuliani at the White House’s annual Hanukkah party in 2018. Still, Pence and his aides insist the vice president has no relationship with Parnas, whose documents and recent interviews have fanned the impeachment flames heading into the president’s Senate trial.

“I don’t know the guy,” Pence said Thursday to reporters traveling with him in Central Florida. The vice president added that Parnas’ charge that he was aware of the Trump team’s outreach to Ukraine to obtain a Biden probe was “completely false.”

Pence chief of staff Marc Short also shot back at Parnas, who was indicted in October on campaign finance charges, arguing that he “will say anything to anybody who will listen in hopes of staying out of prison.”

Part of Pence’s balancing act will include sticking to a series of previously scheduled campaign events in key 2020 states. In addition to his overseas trip to Italy to see the pope — which will also include a stop in Israel — the vice president was in Memphis this past weekend to tour a civil rights museum and deliver remarks honoring Martin Luther King Jr. ahead of the federal holiday commemorating the civil rights leader’s birthday. Next week, he will travel to Iowa for a series of campaign events with military veterans and evangelical conservatives.

“Because it’s an election year, he will be on the campaign trail since a lot of that stuff is planned in advance,” said a former Pence aide. “But a lot of people will be watching what he’s doing, which will obviously cause him to have an even more loyal posture since you don’t want anyone to misconstrue your intentions.”

Gore was similarly under close scrutiny by reporters, voters, and the president’s Democratic allies while the Senate deliberated the articles of impeachment against Clinton. The former vice president kept a packed schedule. He swore in a new batch of 34 senators, delivered remarks at the annual World Economic Forum in Davos, Switzerland, and visited Iowa to discuss pork production, domestic violence, education, drugs and alcohol abuse.

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In one-on-one interviews — something Pence will do during his overseas trip this week, according to people familiar with his plans — Gore portrayed himself as Clinton’s biggest cheerleader.

“I know there is a big disconnect between part of the Republican party, including the Republican leadership in the House of Representatives, for example, and the rest of the American people where President Clinton is concerned,” Gore told the Associated Press in Des Moines on Jan. 9, 1999, two days into the president’s trial and a little more than a week after the Tennessee Democrat filed the official paperwork required to run for the White House.

It wasn’t easy for the vice president to run a presidential campaign and mount a full-scale defense of his boss. He was chided for campaigning on the administration’s accomplishments while barely addressing the president’s controversial actions.

Gore’s difficulties could be foretelling as Pence sets out to make his case for a second term. The vice president’s detractors say he similarly champions Trump’s record without even acknowledging the omnipresent scandals.

And interestingly enough, some of the people who went after Gore over the issue will be deciding Trump’s fate.

“It is hard for Vice President Gore to take credit for everything going well and take none of the blame for the national embarrassment that Bill Clinton has caused,” future Tennessee Republican Sen. Lamar Alexander told The Washington Post at the time, as he plotted his own ill-fated White House bid.