• Democrats are using old clips of President Donald Trump’s remarks to undermine his own defense during the ongoing Senate impeachment trial.
  • Republicans have barred new witnesses from appearing in the trial – but, according to a clip from December that was played on Thursday, the president himself said he wanted to hear testimony from top White House officials.
  • In another clip from October, that was also played during the trial, Trump had said of Ukraine: “They should investigate the Bidens.”
  • Clips of Trump’s prominent defenders were also played at the trial, including one in which Sen. Lindsey Graham can be seen in 1999 flatly contradicting his current position on impeachment.
  • Visit Business Insider’s homepage for more stories.

Republicans have stuck to a central argument in their defense of President Donald Trump in the impeachment trial: that in seeking an investigation of Ukrainian energy firm Burisma – where former Vice President Joe Biden’s son, Hunter, worked – Trump was simply acting out of concern to address corruption in Ukraine.

There’s just one person whose words and actions keep blowing up that defense – the president himself.

During impeachment proceedings this week, Trump’s voice rang through the Senate chamber as Democrats played multiple clips which they claim show Trump clearly unconcerned with tackling corruption in Ukraine, but rather with securing information to damage Biden.

Implicating Biden, a frontrunner in the race for the 2020 Democratic Party nomination for president, in a Ukrainian investigation into corruption would tarnish Biden’s image and help Trump in his bid for re-election later this year.

'From the president's own words...'

A clip from last October, in which Trump doubled down on his call for Ukraine to announce an investigation into Biden, and again called on China to get involved and launch its own Biden probe.

"Well, I would think that if they were honest about it, they'd start a major investigation into the Bidens. It's a very simple answer," said Trump of Ukraine at the time.

"So here we hear again from the president's own words what his primary object is," Rep. Adam Schiff, the lead House impeachment manager at the Senate trial, told the upper chamber Thursday.

"And his primary object is helping his re-election campaign, help to cheat in his re-election campaign."

Schiff also used a clip of the president from last December in his argument against the Republican decision to barr new witnesses from testifying.

"I would love to have Mike Pompeo and Mick [Mulvaney, his Chief of Staff] and I would love to have [Energy Secretary] Rick Perry, and many other people testify," the president said at the time.

But it is worth noting that in the full clip - which wasn't played - Trump did go on to say: "I don't want them to testify when this is a total fix," referring to impeachment proceedings.

Top Trump defenders aren't safe from scrutiny either

The president isn't the only one whose words are being turned against him - his top impeachment allies are, too.

Trump's legal team and many Republicans, including Sen. Lindsey Graham, are arguing that that only a crime can be grounds for impeaching a president, and removing them from office.

Abuse of power and obstruction of Congress, the charges used to impeach Trump, are simply not crimes so can't be used to impeach, he has said.

But in footage played by Democrats Thursday, from President Bill Clinton's impeachment trial in 1999, Graham can be seen arguing for a very different position.

"I think that's what they meant by high crimes. Doesn't even have to be a crime. It's just when you start using your office and you're acting in a way that hurts people, you've committed a high crime," Graham said at the time.

Trump's no-holds-barred, unfiltered style is at the heart of his appeal to his supporters, and it's not the first time his own words have been returned to haunt him.

During legal battles over Trump's hardline anti-migration policies last year, lawyers successfully argued that his long record of racist remarks undermined his argument and exposed his real motivation.