Scott Marinoff told me about this. The Nixon Library in Yorba Linda, California recently released nearly 100,000 pages of presidential records and eighty hours of videotaped interviews relating to the 37th president of these United States. Included in the batch was this letter (PDF file) penned on February 21, 1973. In it, John D. Ehrlichman, who was then the Assistant to the President for Domestic Affairs wrote to cartoonist Garry Trudeau to request the original art to a Doonesbury Sunday page — the one for February 11, 1973.
It's one of those strips in which every panel is the same long shot of the White House and we "hear" voices coming from within — in this case, both ends of a phone conversation between Richard M. Nixon and his wife Pat, who are in different sections of the building. Nixon says to his spouse, "I have this nagging feeling I've forgotten to do something today" and he asks her to read him a copy of a schedule he left in the pocket of his other suit.
She reads it to him and there's three hours alloted for one foreign affairs meeting and two hours for another and so on…until she gets down to "Domestic Affairs — 4:00 – 4:15" and Nixon cries, "That's it!"
That's the page Ehrlichman, who was in charge of meeting with Nixon about Domestic Affairs, wanted to hang on his wall along with other comic strip originals he owned, including a Pogo and a Broom Hilda. There is no information as to whether he received it and no info as to whether he later put any of his comic strip collection up in his cell. On April 30 of that year in connection with the Watergate scandal, Nixon requested and got the resignations of Ehrlichman and his fellow advisor H.R. Haldeman. On January 1, 1975, Ehrlichman, Haldeman and former Attorney General John Mitchell were convicted of multiple Watergate-related crimes and sent to prison for, in Ehrlichman's case, eighteen months.
There's also no information as to whether Mitchell ever requested the infamous Doonesbury strip for May 19, 1973 in which he was proclaimed as "Guilty, guilty, guilty." But I suspect not.