Mercier's letter labeling Dreyfus “Lowlife D”

Mercier's letter labeling Dreyfus Lowlife D is a document that Auguste Mercier continued to use against Alfred Dreyfus despite having received a decryption showing that it could not refer to him. Its return as evidence at the Rennes trial turned a secret-dossier accusation into a visible contradiction: the former minister presented the letter as proof of guilt after he had already been given grounds to reject that attribution.

The letter as evidence

During his three-hour deposition, Mercier produced document after document from a black leather case. Among them was the letter, which he continued to insist referred to Dreyfus. He passed the papers to Jouaust, who handed them along the line of judges, bringing the disputed document into open court.

The letter appeared alongside the fabricated Guénée reports about a spy in the intelligence department. Mercier left out the source’s name, Val Carlos, while presenting the reports as part of his case. In that setting, the letter was not an isolated item: it belonged to a sequence of documents used to sustain the accusation. By placing secret-dossier material before the judges in public, however, Mercier also created an opening for Fernand Labori to challenge how that evidence had been handled.

Knowledge that contradicted the claim

The later exchange between Labori and Picquart established the central problem with Mercier’s use of the letter. Labori asked whether the decrypt had been shown to Mercier; Picquart confirmed that it had been handed to him personally. Labori then drew out the implication: Mercier must have known more than a month before the court-martial that the letter could not refer to Dreyfus.

The force of the contradiction lies in the sequence. Mercier had received information that undermined the letter’s attribution before the trial, yet he went ahead and showed it to the judges with commentary emphasizing its importance in proving Dreyfus’s guilt. The issue was therefore not merely that the document was misleading; the testimony made Mercier’s prior knowledge part of the account of how it was used.

Repetition and exposure

The letter’s significance sharpened when Picquart noted that Mercier had maintained the same position the day before. The accusation survived not as an old mistake quietly abandoned, but as a claim Mercier continued to defend after the contrary information had reached him. That persistence connected the original use of the document at Dreyfus’s court-martial to its renewed presentation at Rennes.

The court scene also reverses the letter’s intended force. Produced to reinforce Dreyfus’s guilt, it instead exposed the gap between the evidence Mercier had received and the case he continued to present. Its appearance in open court made the secret dossier available for scrutiny and gave Labori a concrete basis for questioning Mercier’s conduct.