Speaking from the Senate floor in the impeachment trial of President Trump this week, Alan Dershowitz presented the American people with a vision of Congress’s impeachment power that is sharply at odds with the Constitution, the deliberations of the Framers and the history of impeachments.

His claim — central to Trump’s defense — is that “purely noncriminal conduct, including abuse of power and obstruction of Congress, are outside the range of impeachable offenses.” Although he says a “technical” crime is not required, he means only that criminal conduct can still be impeachable even if it cannot be prosecuted for some jurisdictional or procedural reason.

The Constitution states that the president “shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.” Dershowitz asserts that by including the word “other” before “high Crimes and Misdemeanors,” the Framers intended to limit impeachment to “criminal-like conduct akin to treason and bribery.”

It’s among the many theories Trump’s team has deployed to excuse the president’s misconduct. And it was the reason given by Sen. Lamar Alexander (R-Tenn.) on Thursday night for not calling additional witnesses in the trial. “Even if the House charges” against the president “were true,” Alexander said, “they do not meet the Constitution’s treason, bribery, or other high crimes and misdemeanors standard for an impeachable offense.”

But thanks to James Madison’s record of the 1787 Constitutional Convention, we know a lot about the development of the impeachment power. While a few Framers argued that the president should not be impeachable, Madison “thought it indispensable that some provision should be made for defending the Community agst. the incapacity, negligence or perfidy” of a president. Other convention delegates sought to constrain abuse of power, corruption of electors, betrayal of trust to foreign powers, bribery and more. They settled on a formulation close to what we have today, with the term “high” meaning that impeachable offenses relate to high, or public, office.

Despite his desire for a broad impeachment power, Madison was concerned about trying the president “for any act which might be called a misdemesnor,” warning the other convention delegates that “The President under these circumstances was made improperly dependent” on the legislative branch.

History has proved Madison wrong on this point. Three presidents have been impeached by the House of Representatives, but the Senate has never removed a president from office. Madison’s notes, however, call attention to something that Dershowitz gets wrong:

Dershowitz relies on the notion that “crimes” and “misdemeanors” are synonymous — both are, in his words, “a species of crime.” That conclusion is key to his theory that impeachable conduct involves only criminal offenses akin to treason and bribery, not any other type of misconduct.

To make his point, he cites Supreme Court Justice Benjamin Curtis, a defender in President Andrew Johnson’s impeachment trial. Curtis noted that, under our Constitution, the president may pardon “Offenses against the United States, except in Cases of Impeachment.” But this language merely shows that impeachments may involve offenses under federal law. It doesn’t mean that crimes and misdemeanors are the same. Again citing Curtis, Dershowitz highlights another constitutional provision: “The Trial of all Crimes, except in Cases of Impeachment; shall be by Jury.” This is also true, but it doesn’t prove that an impeachment must involve crimes.

The impeachment provision’s structure and earliest application also undermine Dershowitz’s argument. In Britain, high crimes and misdemeanors referred to two distinct categories of wrongdoing. If the Framers were aware of this, and did not intend such a reading, then they could have chosen a different construction. If the Framers were unaware, and intended to equate high crimes with high misdemeanors, then the phrase is redundant. They could have written “high crimes” alone to convey the same meaning.

In any case, Madison’s specific concern about trying misdemeanors makes sense only if the word has a meaning different from crimes. Take, for example, the 1804 impeachment trial of Judge John Pickering. The Senate removed him from office for, among other things, drunkenness and profanity on the bench — a far cry from crimes akin to treason and bribery.

Dershowitz, though, says the Constitution establishes a lower standard for impeaching judges, because judges “shall hold their Offices during good Behaviour.” But he disregards the history of this phrase. It means that judges do not serve for a term of years, as do members of Congress and the president, so their lifetime tenure is limited only by impeachment as set forth in the same provision that applies to the president, vice president and other civil officers.

Perhaps recognizing the weakness of his position, Dershowitz rests heavily on an alternative argument: Even if criminal-like conduct is not required for impeachment and removal, the articles of impeachment that charge abuse of power and obstruction of Congress are deficient because they employ “vague, open-ended and entirely subjective” criteria.

He highlights the Framers’ express rejection of “maladministration” as a basis for impeachment, which would, in Madison’s words, make the president’s term “equivalent to a tenure during pleasure of the Senate.” Dershowitz then jumps, without support, to the conclusion that the Framers also would have rejected impeachment on the charge of abuse of power, likening it to the idea of maladministration.

But maladministration means, literally, bad administration; the term can encompass mediocre decision-making or basic policy disputes. Abuse of power, by contrast, involves the misuse of official authority to serve personal or other illegitimate interests. The former can mean many things, while the latter has clear components that can be proved or refuted.

Far from being rejected as impeachable conduct, abuse of power animates the Constitution’s impeachment power.

At the Constitutional Convention, when a draft provision contained only the criteria of treason and bribery, George Mason warned that these terms alone “will not reach many great and dangerous offences” and would not constrain “Attempts to subvert the Constitution.” In short order, the phrase “or other high Crimes and Misdemeanors” was added.

This alteration expanded the impeachment power to a wide range of offenses, often without a precise analogue in ordinary law, including abuses of power, high offenses that negatively affect the constitutional order. Alexander Hamilton, in “The Federalist No. 65,” describes such acts as “those offenses which proceed from the misconduct of public men, or, in other words, from the abuse or violation of some public trust.”

Because Dershowitz does not recognize this class of offenses as impeachable, he backs into a position that would prove fatal to our system if accepted by the Senate: “If a president does something,” he said, “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.” Against the warnings of the Framers that a president might abuse power to win elections or become entangled with a foreign government, he suggests that there “cannot be a corrupt motive” for an official act the president takes to help further his electoral interests, provided it does not advance his financial interests.

This dangerous standard would permit the current president, or any president, without consequences, to engage in corrupt acts that violate the public trust. It would contravene the Constitution’s command that the president “shall take Care that the Laws be faithfully executed.” It would mean the president’s power would go largely unchecked by Congress — transforming our constitutional republic into a virtual monarchy.

These errors are so acute that one suspects Dershowitz started with his opposition to this impeachment and worked backward to engineer a constitutional theory to justify his position. He presented his thesis as a considered legal argument. Instead, he offered a proverbial Hail Mary — an ahistorical case for an impeachment standard unsupported by the Constitution’s text or the history of the impeachment power, and one that does not exonerate the president. The Senate must reject it.