US President Donald Trump. Picture: AFP/NICHOLAS KAMM
US President Donald Trump. Picture: AFP/NICHOLAS KAMM

As Republicans scramble to argue that they don’t need to call witnesses in Donald Trump’s Senate impeachment trial, one argument seems to be gaining traction: that witnesses are irrelevant, because even if Trump did everything he’s accused of doing, abuse of power is not an impeachable offence.

This argument isn’t merely wrong. It is the single most dangerous argument that any of Trump’s defenders have made during the entire impeachment process. If abuse of power isn’t impeachable, what is?

The strongest version of this argument has been made by Alan Dershowitz, who has insisted that the constitution’s “high crimes and misdemeanours” include only crimes found in the statute books, not abuse of power.

That’s obviously wrong. In 1725, in a case the framers knew, Thomas, Earl of Macclesfield, was impeached by the House of Commons specifically for “abuse of his power” and “great abuse of his authority”. The House of Lords convicted him for it.

At the constitutional convention, on July 20 1787, Edmund Randolph, the governor of Virginia who had introduced the Virginia plan, stated specifically that “the propriety of impeachments was a favourite principle with him” because the “executive will have great opportunities of abusing his power”. In Federalist 65, Alexander Hamilton defined high crimes and misdemeanours as “those offences which proceed from the misconduct of public men, or, in other words, from the abuse or violation of some public trust”.

Dershowitz’s view is so absurd that I don’t know of even one legal scholar who studies the constitution who agrees with him. That includes Dershowitz himself, who in 1998 said (correctly) that impeachment doesn’t have to be for a crime.

Seeking scholarly support, Dershowitz has repeatedly misrepresented the work of my colleague Nikolas Bowie. Bowie has rejected Dershowitz’s claim, explaining that abuse of power is a perfectly valid example of a high crime or high misdemeanour. Dershowitz’s misleading characterisation of Bowie’s work derives from an article in which Bowie argued that high crimes and misdemeanours must be recognised crimes under either the unwritten common law or under written statutes. Abuse of power by government officials was a well-recognised crime under the common law, as the framers knew.

Dershowitz speciously says that because today’s courts do not recognise federal common law crimes, abuse of power can’t be impeachable. That’s literally laughable: when the framers wrote the constitution, there were no federal statutory crimes, because there was no US code. So, according to Dershowitz, the framers wrote an impeachment provision that did not allow them to impeach anyone.

What’s so dangerous about this perspective, however, isn’t only that it radically distorts the entire history and meaning of the constitutional practice of impeachment.

What makes it scary is that it amounts to the view that even if Trump extorted the president of Ukraine to force him to announce an investigation targeted at his leading political opponent, the constitution doesn’t allow his removal. That would lead to a world where the president could break the democratic system by targeting his political opponents through the powers of his office.

Think about it. A president could ask the department of justice and the FBI to open criminal investigations against candidates running against him — through the exercise of his official duties as head of the executive branch and boss of the attorney-general. He could use the power of the presidency to force the governments of other countries to open such investigations, which is exactly what Trump is alleged to have done. According to the view that abuse of power isn’t an impeachable offence, this would all be fine.

“Every public official that I know believes that his election is in the public interest,” Dershowitz said Wednesday. “And 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.”

But using the powers of the president’s office to target an opponent as a political dirty trick undercuts democracy itself. On Dershowitz’s theory, blackmailing an opponent to drop out using information obtained by government surveillance would not be impeachable.

It is sometimes argued that sitting presidents always use the power of their office to try to get votes. Unlike the challenger candidate, a sitting president can command headlines by issuing new executive orders, for example. For the most part, though, such actions aren’t a problem: in democracy, the person in office is supposed to take policy actions that will garner public support. We don’t ask them to stop running the country while they run for re-election.

But that’s different from a president using the powers of his office to compel a foreign leader to target one of his political opponents.

To any unbiased observer, this conclusion should be obvious. Can Republican senators really say with a straight face that it is perfectly fine for a president to use his office to target his political opponent for criminal investigation during an electoral campaign? No.

The worst possible outcome for this impeachment process would be for Republicans to coalesce around the idea that Trump did everything he’s been accused of in the articles of impeachment but had every right to do so under the constitution. A democracy where that view holds sway among the majority of one branch of the legislature is a democracy in deep trouble.

• Feldman is a Bloomberg opinion columnist.

Bloomberg