18 U.S.C. § 1734
Editorials and other matter as “advertisements”
Whoever, being an editor or publisher, prints in a publication entered as second class mail, editorial or other reading matter for which he has been paid or promised a valuable consideration, without plainly marking the same “advertisement” shall be fined under this title.
(Added Pub. L. 86–682, § 7 , Sept. 2, 1960 , 74 Stat. 706 ; amended Pub. L. 103–322, title XXXIII, § 330016(1)(G) , Sept. 13, 1994 , 108 Stat. 2147 .)