Retired Harvard law professor Alan Dershowitz argued in President Trump’s impeachment trial Wednesday that the president’s demand for Ukraine to investigate former Vice President Joe Biden — a leading candidate to oppose him in the presidential campaign — is not an impeachable offense because Trump was acting on the belief that his reelection is “in the public interest.”

“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 an impeachment,” Dershowitz said in response to Sen. Ted Cruz, R-Texas, on the first of two days during which the opposing legal teams answer written questions from the senators.

Cruz had asked, “As a matter of law, does it matter if there was a quid pro quo?”

Trump has repeatedly denied the existence of a quid pro quo in his dealings with Ukraine, but that defense suffered a blow with the disclosure that his former national security adviser John Bolton has firsthand evidence that the president intended precisely that. Accordingly, his lawyers have shifted to the argument that even if there was one, it does not rise to the level of an impeachable offense.

But Dershowitz’s argument seemed to go well beyond that, asserting that a president is entitled to take action that will advance his reelection chances on the basis of his own belief that it’s for the good of the country — as Abraham Lincoln did in 1864, ordering that troops from Indiana be given leave to return home to vote in an election to keep the state government in Republican hands.

Dershowitz offered the hypothetical scenario of a Democratic president offering a quid pro quo to help solve the Israeli-Palestinian conflict — a long-standing goal of American foreign policy that if successful would also boost his or her reelection prospects.

The president’s lawyer and frequent defender on Fox News — who nevertheless says he didn’t vote for him and opposes many of his policies — did not address the fact that in (allegedly) withholding military aid to Ukraine in exchange for electoral help, Trump was in fact acting against official U.S. policy, which was to aid that country in its war with Russia.

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“We may argue it’s not in the national interest for a particular president to be reelected,” Dershowitz told the Senate, “but for it to be impeachable you would have to discern that he or she made a decision solely on the basis of, as the house managers put it, corrupt motives.”

He added: “It is so dangerous to try to psychoanalyze a president to try to get into the intricacies of the human mind. Everybody has mixed motives.”

“[Dershowitz] just argued that a president who believes only he can fix it — who thinks his re-election is vital to the nation — can’t be impeached for abusing his power to corrupt the next election in his favor because by definition he’s doing what he thinks best for the country!!” tweeted Laurence Tribe, a Harvard law professor and a constitutional scholar who is frequently at odds with Dershowitz.

“Accepting this argument would put us on a short path toward dictatorship, benevolent or otherwise. It’s incompatible with government of, by, and for the people,” Tribe added. “It’s government by egomania.”

Taking the argument to a reductio ad absurdum, the Atlantic magazine’s Adam Serwer wrote on Twitter: “If the president drops nuclear bombs on New York and California to neutralize their electoral votes because he believes it is in the national interest, it is not impeachable, according to Alan Dershowitz.”

“The president lawyers are arguing that if the president ordered his election opponent arrested that would be fine because he’s pursuing the national interest in order to get re-elected,” MSNBC’s Chris Hayes tweeted. “Just to be clear this is the unavoidable logical extension of Dershowitz’s argument.”

In response to a follow-up question from Senate Democratic leader Chuck Schumer, Adam Schiff, the lead impeachment manager for House Democrats, countered with a hypothetical of his own: What if, in 2011, President Barack Obama had asked Russia to launch an investigation into Mitt Romney, his Republican opponent in the 2012 election, in exchange for U.S. military aid?

“Do any of us have any question that Barack Obama would be impeached for that kind of misconduct?” Schiff asked. “Are we really ready to say that would be OK?”

“All quid pros are not the same,” Schiff added. “Some are legitimate and some are corrupt. You don’t have to be a mind reader to figure out which are which. For one thing, you can ask John Bolton.”

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