The television show 21 Jump Street, about cops who go undercover as high schoolers, debuted on Fox in 1987 and ran until 1991. As a sign of the progress made since the Reagan/Bush era, the mixed-bag big-screen 21 Jump Street mocks the program’s lethal earnestness with retrograde raunch, packing in more references to dick-sucking than 20 Manhunt profiles. The series, with its coed, mixed-race quartet of baby-faced police officers, has been retooled as a white-dude buddy action-comedy that announces its cynicism from the start. After Schmidt (Jonah Hill) and Jenko (Channing Tatum), rookie cops who knew each other in high school in the mid ’00s, botch an arrest, their supervisor reassigns them to a new detail, described as a project from the ’80s now being revamped: “All they do now is recycle shit from the past and expect nobody to notice.” Its own superfluousness readily acknowledged, 21 Jump Street tries—and sometimes succeeds—to get laughs from Schmidt and Jenko’s redo of senior year as 25-year-olds. Dispatched to infiltrate a high-school drug ring by Jump Street’s captain (Ice Cube, hilarious), Schmidt, a pariah during his real high-school years, is, in 2012, tight with today’s cool kids; Jenko, a thick former varsity footballer, must now fake his way through AP chemistry. Although they bounce well off each other, Tatum, in his first comic lead role, is the better performer, both more riotous and affecting; Hill, on the other hand, relies on the same tics that have defined him since Superbad: the nervous overexplaining of the underconfident smart aleck.