[5] On September 26, 2024, Klippenstein shared a dossier on vice-presidential candidate JD Vance, reportedly hacked from the Trump campaign and subsequently leaked by Iran, in his newsletter and linked to it from his X account.

[21] On December 10, 2024, Klippenstein published an alleged full text manifesto of Luigi Mangione, the suspect in the killing of Brian Thompson.

[22] In an interview with Democracy Now!, Klippenstein blamed paternalistic attitudes in corporate media and the possibility of alienating law enforcement sources for the reluctance to publish the alleged manifesto's full text.

[23][24] Klippenstein is a self-described "FOIA nerd"; much of his journalism draws on information he has uncovered from records requested at state and national levels of the US government.

[27][28] In an April 2020 article, Klippenstein reported on a leaked document showing that the Pentagon had warned the White House in 2017 about the risk of shortages and ill-preparation for a pandemic brought on by a novel coronavirus such as SARS-CoV-2.

[35][36] Later, he co-authored with Lee Fang an article published by The Intercept in October 2022 regarding leaked documents exposing Department of Homeland Security's plans to secretly police disinformation online.

[37][38] In response, Klippenstein was interviewed on Useful Idiots, where he expressed concern about what he saw as a major media failure regarding intelligence information oversight in a situation with no one in control as things drift toward disaster.

[48][49][50] In March 2021, Klippenstein pranked author Naomi Wolf by recommending she tweet an image of a fabricated anti-vaxxer quotation paired with a picture of American pornography actor Johnny Sins.