Alan M. Dershowitz, a law professor at Harvard, wrote on FoxNews.com Wednesday that President Trump has the constitutional right to direct his FBI director to stop an investigation of anyone “by simply pardoning that person.”

“Throughout American history-- from Adams to Jefferson to Lincoln to Roosevelt to Kennedy to Obama-- presidents have directed (not merely requested) the Justice Department to investigate, prosecute (or not prosecute) specific individuals or categories of individuals,” Dershowitz wrote. “It is only recently that the tradition of an independent Justice Department and FBI has emerged. But traditions, even salutary ones, cannot form the basis of a criminal charge.”

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Dershowitz wrote the column after fomer-FBI Director James Comey's prepared remarks were released ahead of his appearance on Capitol Hill on Thursday.

Comey is set to testify that Trump sought his “loyalty” and asked what could be done to “lift the cloud” of investigation shadowing his administration. The prepared remarks detail a series of conversations between Trump and Comey about the investigation into contacts between the Trump campaign and Russia, and Comey's discomfort with the interactions.

Other legal experts say the most damning statement in Comey's written testimony concerns former National Security Adviser Mike Flynn, who was under investigation for making false statements about contacts with Russian officials.

Trump asked Attorney General Jeff Sessions and other top government officials to leave the Oval Office on Feb. 14 before urging Comey to drop the investigation of Flynn. "I hope you can let this go," Trump said, according to Comey's testimony.

Dershowitz, however, wrote that the written statement “does not provide evidence that President Trump committed obstruction of justice or any other crime.”

Obstruction of justice is a federal crime, though it's an open question whether a sitting president can be prosecuted. It's also an impeachable offense, though Republicans who control Congress are extremely unlikely to go after a president of their own party.

Dershowitz wrote, “Assume, for argument’s sake, that the president had said the following to Comey: “You are no longer authorized to investigate Flynn because I have decided to pardon him." Would that exercise of the president's constitutional power to pardon constitute a criminal obstruction of justice? Of course not. Presidents do that all the time.”

Other legal experts see the statement differently.

Julie O'Sullivan, a former federal prosecutor who teaches at Georgetown University's law school, told the Associated Press Trump's decision to clear the room before talking to Comey is evidence that suggests that Trump "was aware that what he was doing was a problem."

Trump has previously denied that he told Comey to end the investigation.

A former FBI official and a prominent Washington, D.C., law professor told the AP that they don't see a crime in what Comey reported that Trump said. Instead, the document reveals a president woefully ignorant of standard protocol and of the historic wall of independence between the FBI and the White House, an inexperience that could work in his favor and make his actions simply improper instead of actually illegal.

"I think the request is inappropriate," said Andrew Arena, a retired senior FBI official. "Whether it crosses that threshold to being criminal, I'm not there yet."

The Associated Press contributed to this report