Harvard Law Professor Alan Dershowitz, a member of President’s Trump's impeachment defense team, argued Wednesday that former Vice President Joe Biden’s presidential candidacy justifies the president wanting to investigate his son Hunter's involvement with a Ukrainian oil company.

“The fact that he’s announced his candidacy is a very good reason for upping the interest in his son,” Dershowitz said, adding that the House managers would agree that Trump running for re-election is the only reason it could be an impeachable offense.

Dershowitz asserted that, hypothetically, if Trump wanted Hunter Biden investigated for alleged corruption in his second term it wouldn't be impeachable.

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“The difference, the House managers would make, is whether he’s in his first term or his second term, whether he’s running for re-election or not running for re-election," he said. "If he’s running for re-election suddenly that turns it into an impeachable offense."

Dershowitz added that even if there was a quid pro quo by withholding $391 million in military aid to Ukraine it wouldn’t matter because “if a president does something which he believes will help him get elected in the public interest, that cannot be the kind of quid pro quo that results in impeachment.”

He suggested Trump’s alleged request for investigations during the July phone call with Ukrainian President Volodymyr Zelensky was a “mixed motive,” meaning Trump believed it would benefit both the country and incidentally himself.

The House managers have argued that Trump abused his power in asking Ukraine to meddle in a U.S. election by investigating the son of his political rival.

"If you say you can’t hold a president accountable in an election year where they are trying to cheat in that election, then you are giving them carte blanche,” House manager Adam Schiff responded. “So all quid pro quos are not the same. Some are legitimate, and some are corrupt and you don’t need to be a mind reader to figure out which is which.”

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Democrats have also said that if Trump was legitimately concerned about corruption involving Hunter Biden, he should have called for the Justice Department to launch an official investigation.