But most legal scholars disagree, including a law professor called by Republicans in the House investigation to argue against impeaching Trump.
A lawyer for Johnson argued in his opening statement to the Senate that Johnson could not be removed from office because he was not guilty of a crime. Johnson was acquitted by a single vote. One of Trump's lawyers, Alan Dershowitz says that same argument — that impeachment requires "criminal-like conduct" — will be central to the constitutional defense he will make on the president's behalf.
The idea may be attractive to Republicans seeking a legal basis to acquit Trump of having abused his power and obstructing Congress. But legal scholars dispute the idea that the Founding Fathers ever intended for impeachable offenses to require proof of a crime. And historians are equally dubious that the argument from Johnson's lawyer, Benjamin Robbins Curtis, can be credited with securing Johnson's narrow acquittal.
“This is a way in which history is weaponized and distorted in order to give these kinds of arguments heft," said Rachel Shelden, a Penn State University history professor and Civil War-era expert. “It's a way of trying to promote an understanding of the Johnson impeachment that is false, based on what historians now believe."
At issue is the Constitution's standard for impeachment: “treason, bribery, or other high crimes and misdemeanors." Over the centuries, the threshold has been understood to encompass actual crimes — judges have been impeached for sex abuse and soliciting bribes, among other offenses — but also noncriminal misconduct such as being drunk on the bench or favoritism in the appointment of bankruptcy receivers.
Johnson was impeached over accusations that he violated the Tenure of Office Act, which barred presidents from firing certain officials without Senate approval, over his removal of War Secretary Edwin Stanton.
Johnson's defense team questioned the constitutionality of that now-extinct law, and at his 1868 trial, one of his lawyers asserted in his opening argument that an impeachable offense “refers to, and includes only, high criminal offenses against the United States."
“There can be no crime, there can be no misdemeanor without a law, written or unwritten, express or implied," said Curtis, a former Supreme Court Justice. "There must be some law; otherwise there is no crime. My interpretation of it is that the language ‘high crimes and misdemeanors' means ‘offenses against the laws of the United States.'"
Dershowitz, who is expected to make a constitutional presentation to the Senate within days, said Sunday on CNN's “State of the Union" that he would paraphrase Curtis's argument that “the framers intended for impeachable conduct only to be criminal-like conduct or conduct that is prohibited by the criminal law."
“That argument prevailed. I will be making that argument as a lawyer on behalf of the president's defense team against impeachment. That's my role. It's very clear. I have done it before," Dershowitz said.
Republican senators may well embrace the argument. One, Sen. John Cornyn of Texas, told reporters Wednesday that anyone charged with wrongdoing has the right to know what law or standard they're accused of violating.
“This idea that you can use abuse of power as a grab bag in which to stuff all your political, policy or personal grievances — I think is very dangerous," Cornyn said.
But legal scholars and Democrats are decrying the claim that an impeachable offense must be an indictable crime.
Frank Bowman, a University of Missouri law professor and former student of Dershowitz's at Harvard Law School, described it as “rubbish." Jonathan Turley, a George Washington University law professor who argued to the House against impeachment, wrote in The Washington Post on Wednesday that such an argument was politically unwise and constitutionally shortsighted.
“They had to go outside the realm of constitutional lawyers and scholars to a criminal defense lawyer to make that argument because no reputable constitutional law expert would do that," said California Rep. Adam Schiff, chairman of the House Intelligence Committee. He is one of the seven Democratic managers prosecuting the impeachment case.
Even Trump's attorney general, William Barr, wrote in a June 2018 memo before he was nominated for the Cabinet post that Congress could impeach presidents who abused their power.
Democrats say Trump's abuse of power — pressing Ukraine for an investigation into a Trump Democratic rival, Joe Biden, at the same time his administration withheld millions of dollars in military aid — is a “quintessential impeachable offense." They say the Founding Fathers intentionally created a flexible standard of bad acts that could result in impeachment, and that Trump's acts in this instance are the framers' “worst nightmare."
Historians also point to multiple reasons for Johnson's acquittal and are skeptical that senators at the time found Curtis' arguments persuasive.
Had Johnson been removed from office, he would have been temporarily succeeded by Benjamin Wade, the Senate president and a radical Republican disliked by more conservative Republicans. Behind the scenes, Johnson and his allies worked to assure senators that if they voted to acquit him, he would stop interfering in Reconstruction. That was the very concern that led to Johnson's impeachment in the first place. And there's some agreement among historians that the senator who cast the deciding vote against impeachment was bribed.
“I don’t think you can place any weight on that argument for explaining Andrew Johnson's acquittal," said Jeffrey Engel, director of Southern Methodist University's Center for Presidential History and co-author of “Impeachment: An American History."
The Constitution's framers seemed more preoccupied by the notion of a president's “faithfulness to the office" than on the precise acts that would merit impeachment, said Kent Greenfield, a Boston College constitutional law professor.
“What that means is faithful as opposed to corrupt, faithful as opposed to self-interested," Greenfield said. “There's something like a fiduciary duty to the nation. That duty is really more than just, 'Don't break the law.'"
It means, Greenfield said, putting the interests of the country above personal interests.
Even if the argument that impeachment requires a crime isn't the best legal one, it may nonetheless be worth making to senators, “who are not judges" and “may be persuaded by arguments that aren't terribly good law," said David Stewart, a historian who has written a book about Johnson's impeachment.
“I'll be blunt: If I was the president's lawyer, I'd probably make the argument too," Stewart said. “But I don't think it's very strong."
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