You can make the case that the White House Chief of Staff is the second most powerful person in the country, James Baker, who had that title under Reagan. A look at the little examined office is offered in the two night special “The Presidents’ Gatekeepers” (Discovery, 9 p.m.), a more high-minded break from the network that gives you “Amish Mafia” and “Gold Rush.”
The special boasts all 20 living former chiefs of staff, but that number is constantly changing. President Obama named his fourth chief in Denis McDonough in January, his fourth — a number matched only by the two term run of Ronald Reagan.
Why start the series today? Well, a considerable time is spent with Andrew Card, the chief of staff who had to tell George W. Bush that planes crashed into the World Trade Center 12 years ago this morning. He seems very frank about his role, and the lack of preparedness.
A lot of recent history is covered (that is to say, the last 40 years); the position of chief of staff was only first created in the Truman administration. The series concludes Thursday.
The day’s commemoration comes with the usual raft of documentaries. The only new ones are apparently an updated report on the construction of the new One World Trade Center on the 41st season premiere of “Nova” (PBS, 9 p.m.) and “Answering the Call: Ground Zero’s Volunteers” (Destination America, 10 p.m.), narrated by Kathleen Turner.
The rest of them are from past years including “Rebirth” (Showtime, 1 p.m.), “The Man Who Predicted 9/11” (History, 8 p.m.), “George W. Bush: The 9/11 Interview” (National Geographic, 8 p.m.), “9/11 Firehouse” (Discovery, 8 p.m.), “102 Minutes That Changed America” (History, 9 p.m.), “9/11: Where Were You?” (National Geographic, 9 p.m.), “9/11: Surviving” (Destination America, 9 p.m.) and “Witness” (National Geographic, 10 p.m.).
The season four finalists of “MasterChef” (Fox, 9 p.m.) — Luca Manfe, 31, of Astoria, N.Y., and Natasha Crnjac, 26, of San Diego — get to make any dish that they want in hopes of winning the big prize – a trophy, a book deal and $250,000.
“The X Factor” (Fox, 8 p.m.) returns for its third season with its third different judging panel, with Kelly Rowland and Paulina Rubio joining the returning Demi Lovato and Simon Cowell for the first of a series of glossy auditions before arenas full of people. Not to be confused with “X-Men: First Class” (FX, 8 p.m.).
The whole set of coincidences that lead to a killer who not only used to work with Marco but had his family hostage is setting “The Bridge” (FX, 10 p.m.) on an uncomfortable turn.
The second FX show in as many days to fumble gun violence is “It’s Always Sunny in Philadelphia” (FXX, 10 p.m.), in an episode that tries to take on all sides of the issue.
It’s always instructive to remember that Alan Alda first came to fame as a wiseacre on “MASH.” Now he’s just the voice of the wise as he hosts another set of science specials on public television, the latest of which is “Brains on Trial with Alan Alda” (PBS, 10 p.m., check local listings) that looks into advances in neurology and how they might affect the legal process.
Everybody’s back in school, so it’s high time to have a season finale for “Camp” (NBC, 10 p.m.). “Royal Pains” (USA, 9 p.m.) ends its season with labor pains.
The job of solving the murder on “Broadchurch” (BBC America, 10 p.m.) is made more difficult by budget cuts and a newspaper campaign that calls the chief “the Worst Cop in Britain.”
Half of the 12 performers on last night’s show go home on the results show of “America’s Got Talent” (NBC, 9 p.m.).
Termites threaten the “Duck Dynasty” (A&E, 10 p.m.).
The actress Madeleine Stow chooses the films on Turner Classic Movies tonight. Her choices: “The More the Merrier” (8 p.m.), “Splendor in the Grass” (10 p.m.), “The Bicycle Thief” (12:15 a.m.) and “I Confess” (2 a.m.).
Speaking of birds, part two of the visually stunning “Earthflight” on “Nature” (PBS, 8 p.m.) gives a winged creature’s view of Africa.
It’s the last Wednesday show for “Big Brother” (CBS, 8 p.m.). With head of household Spencer having nominated GinaMarie and McCrae, a veto competition is held.
Those waiting in line would do well to know that many of the questions (and questioners) on “Million Second Quiz” (NBC, 8 p.m.) seem to concern NBC Universal shows.
Daytime Talk
Kelly & Michael: Michelle Pfeiffer, Rachael Ray. The View: Keith Urban. The Talk: Craig Ferguson, Michael Chernow, Daniel Holzman. Ellen DeGeneres: Celine Dion. Wendy Williams: LeAnn Rimes, Lilliana Vazquez (rerun).
Late Talk
David Letterman: Joseph Gordon-Levitt, Keith Olbermann, Keith Urban. Jay Leno: Charlie Sheen, Jim Rome, Trombone Shorty. Jimmy Kimmel: Tim Gunn, Preservation Hall Jazz Band. Jimmy Fallon: Ricky Gervais, Michael Shannon, MGMT, Simon Townshend. Craig Ferguson: Max Greenfield, Amy Smart. Carson Daly: Sebastian Junger, Monster Mike Schultz, Joshua James (rerun). Tavis Smiley: B.B. King. Jon Stewart: Bob Odenkirk, David Cross. Stephen Colbert: Sheryl Crow. Conan O’Brien: Rose Byrne, Gov’t Mule. Chelsea Handler: Diana Nyad, James Davis, Heather McDonald, Gary Valentine. W. Kamau Bell: LaVerne Cox.