Cite as: 575 U. S. ____ (2015) 5 THOMAS, J., dissenting the person who, with knowledge or notice of [the paper’s] contents, assumed the responsibility of putting it in the mails of the United States,” because “[e]very one who uses the mails of the United States for carrying papers or publications must take notice of . . . what must be deemed obscene, lewd, and lascivious.” Id., at 41–42. This Court reaffirmed Rosen’s holding in Hamling v. United States, 418 U. S. 87 (1974), when it considered a challenge to convictions under the successor federal stat­ ute, see id., at 98, n. 8 (citing 18 U. S. C. §1461 (1970 ed.)). Relying on Rosen, the Court rejected the argument that the statute required “proof both of knowledge of the con­ tents of the material and awareness of the obscene charac­ ter of the material.” 418 U. S., at 120 (internal quotation marks omitted). In approving the jury instruction that the defendants’ “belief as to the obscenity or non-obscenity of the material is irrelevant,” the Court declined to hold “that the prosecution must prove a defendant’s knowledge of the legal status of the materials he distributes.” Id., at 120–121 (internal quotation marks omitted). To rule otherwise, the Court observed, “would permit the defend­ ant to avoid prosecution by simply claiming that he had not brushed up on the law.” Id., at 123. Decades before §875(c)’s enactment, courts took the same approach to the first federal threat statute, which prohibited threats against the President. In 1917, Con­ gress enacted a law punishing anyone “who knowingly and willfully deposits or causes to be deposited for conveyance in the mail . . . any letter, paper, writing, print, missive, or document containing any threat to take the life of or to inflict bodily harm upon the President of the United States, or who know­ ingly and willfully otherwise makes any such threat against the President.” Act of Feb. 14, 1917, ch. 64, 39 Stat. 919.