A leaked secret Justice Department “white paper” detailing the Obama administration’s legal justification for the targeted drone assassinations of Americans living abroad made its way onto the Internet late Monday evening.

The 16-page white paper — said to be a summary of a longer 50-page document on the highly controversial policy — is seeing the light of day ahead of the Senate confirmation hearing of John Brennan, President Barack Obama’s top pick for CIA chief.

The longer document was written in 2010 to justify the addition of al-Qaida member Anwar al-Aulaqi, a U.S. citizen, to Obama’s secretive “kill list.”

The white paper suggests that the federal government has legal recourse to engage in the extrajudicial assassination of an American citizen, reported NBC News, if “an informed, high-level official” has determined that the American is a “continuing” threat to the country.

The individual would be determined a “continuing” threat if he were “”recently” involved in “activities” posing a threat of a violent attack, and “there is no evidence suggesting that he has renounced or abandoned such activities,” according to the news outlet, which obtained and published the paper.

“The memo does not define “recently” or “activities,” according to NBC News.

Brennan is said to be the policy’s architect.

“Brennan was the first administration official to publicly acknowledge drone strikes in a speech last year, calling them “consistent with the inherent right of self-defense”,” reported NBC News.

“In a separate talk at the Northwestern University Law School in March, Attorney General Eric Holder specifically endorsed the constitutionality of targeted killings of Americans, saying they could be justified if government officials determine the target poses ‘an imminent threat of violent attack,'” wrote the publication.

The paper expands upon the public statements made by Brennan and Holder, according to Jameel Jaffer, deputy legal director at the ACLU.

Jaffer wrote in a blog post that his “initial reaction is that the paper only underscores the irresponsible extravagance of the government’s central claim.”

“Even if the Obama administration is convinced of its own fundamental trustworthiness, the power this white paper sets out will be available to every future president—and every ‘informed high-level official’ (!)—in every future conflict,” said Jaffer.

Follow Josh on Twitter