(CNN) Deputy Attorney General Rod Rosenstein quipped about congressional demands and critics of the Justice Department in a speech Thursday in Chicago that delivered a passive rebuke to his detractors in Washington.

Rosenstein offered no direct critiques -- or specific mention -- of President Donald Trump and his allies on Capitol Hill, who have threatened his job in a battle over access to sensitive documents. But his jokes were telling.

Recalling the words of former Attorney General Edward Levi, who served in Gerald's Ford administration and "devoted his tenure to building public confidence in law enforcement," Rosenstein deviated from his prepared remarks: "Levi, incidentally, also served less than two years. Just saying."

With a reference to Franklin Roosevelt's attorney general, Robert Jackson, whose "tenure was replete with challenges," Rosenstein landed another veiled jab.

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