Former Homeland Security official Miles Taylor today appealed to federal watchdogs to examine whether Trump abused his power when he ordered a review of the ex-official’s conduct.

“This morning, I took the formal step in what will be a long fight: I asked the government’s watchdogs to investigate how Donald Trump is using the presidency to punish dissent — starting with me,” Taylor wrote on Substack.

Taylor, an outspoken critic of the president who worked at the Department of Homeland Security during Trump’s first term, said his request to the inspectors general at the Homeland Security and Justice departments is about safeguarding the constitutional rights of every American. 

“This is about whether the president — any president, from any political party — can order revenge investigations with the stroke of a pen,” Taylor wrote.

Taylor’s move comes after Trump targeted Taylor in a presidential memorandum in April that alleged Taylor was an “egregious leaker,” accused him of potentially “treasonous” actions and ordered authorities to review his conduct while in government.

The inspectors general for the departments did not immediately respond to NBC News’ requests for comment.

In the letter to the inspectors general, Taylor’s lawyer, Abbe Lowell, said Trump’s memorandum was unprecedented in American history because “it explicitly targets a single individual” for government scrutiny. 

“To be clear, we are requesting your Offices do what you are charged with doing — addressing and preventing abuses of power,” Lowell wrote.

Taylor’s case raises “a foundational question of whether, in the United States of America, the machinery of the federal government can be inappropriately deployed against a private citizen in retaliation for exercising constitutionally protected free speech,” he wrote.

The letter asks the inspectors general to investigate whether the Homeland Security or Justice departments have taken actions that constitute retaliation, abuse of authority or violations of Taylor’s constitutional rights. It also asks if any career official has raised objections or concerns about the legality or ethical propriety of carrying out the April 9 presidential memo.

In two presidential memos issued on April 9, Trump singled out Taylor and another former senior official, Chris Krebs, revoking their security clearances and ordering the attorney general to review their actions in government. 

Since then, government authorities have contacted Taylor’s former high school classmates and others associated with him, Taylor told NBC News in an interview last month.

“I have seen indications that they are out there, rummaging through my past, talking to people as far back as high school and trying to comb through my life,” he said.

The memorandum forced Taylor to effectively stop working as a cybersecurity consultant, his family has had to adopt elaborate safety precautions because of online threats directed at him, and some friends and associates have distanced themselves from him to avoid possible retribution by the administration, Taylor and his lawyer said.

Asked for comment, White House spokesperson Abigail Jackson sent a statement reiterating the accusation in the presidential memorandum that Taylor disclosed sensitive information “through unauthorized methods” and attacking Taylor, calling him “a bad faith actor” and saying he should be “embarrassed.”

Taylor has denied any wrongdoing and said he “assiduously upheld my national security obligations.”