Dressed in a baggy T-shirt and dark gray sweatpants, his sleep-tousled hair falling to just above his shoulders, Gabe is sitting up in bed, hunched over his Lenovo laptop, typing away. Within reach are his alarm clock, which went off — as usual — at 5:55 a.m., a recent copy of Time magazine, his iPhone (which he picks up occasionally to check his Twitter feed) and a stack of books he has been reading: “Personal History,” by Katharine Graham; “A Memoir,” by Barbara Bush; “Front Row at the White House,” by Helen Thomas; and “Shattered,” by Amie Parnes and Jonathan Allen, a detailed post-mortem of Hillary Rodham Clinton’s campaign for president in 2016. (“I loved their first book, ‘HRC,’ but I don’t think this one is as good,” Gabe said.)

On the walls of his second-floor, 10-by-12 room (“smaller than my sister’s,” he pointed out) are framed articles from Politico (“Missouri Sixth Grader May Be Next Mike Allen”) and The St. Louis Post-Dispatch (“Fourth Grader Is Political Junkie”). Also, copies of the Declaration of Independence and the first page of the Constitution, a photo of Barack Obama and Representative Lacy Clay, Democrat of Missouri, and an eclectic mix of bumper stickers from the 2016 campaign — for Carly Fiorina, Ben Carson and even the fictional Frank Underwood among them. (“I’m going for a complete collection,” Gabe said.)

Elsewhere are small busts of several presidents; Gabe’s passport to the presidential libraries (so far his has visited all but two of the official ones, Reagan’s and Nixon’s); a miniature replica of the White House; photos of Gabe, his father and his sister, Zoey, at the 2009 Obama inauguration; and one of a 12-year-old Gabe with the historian Doris Kearns Goodwin after a speech she gave in Chicago that Gabe’s grandparents took him to.

And everywhere you look, there are books, books and more books — in a free-standing bookcase, on shelves, on the windowsill and even the floor, all about politics or history, from the four-volume biography of Abraham Lincoln by Carl Sandburg to “The Audacity to Win” by the former Obama campaign strategist David Plouffe (“a great book,” Gabe said).

In fact, it was Mr. Obama’s election as president that set off Gabe’s interest in politics. At age 7, he and Zoey were taken by their father on a last-minute road trip to the inauguration. (Gabe’s mother, Amy, the sales director for Caleres, a St. Louis shoe company, stayed home. “I don’t like to drive,” Mrs. Fleisher explained.)