海角大神

As the story goes, President Lyndon Baines Johnson was giving a speech, and his teleprompter seemed to be working fine. LBJ droned on about some policy or another in his Texas twang, staring into the teleprompter screen, and finished without mangling more words than normal.

Then LBJ walked up to the teleprompter operator and fired him on the spot. The hulking machine 鈥� designed to scroll text in front of a speaker鈥檚 face, so he or she can look directly at an audience 鈥� had malfunctioned, and the operator hadn鈥檛 noticed.

鈥淛ohnson had a blank screen. He鈥檇 just given the speech from memory,鈥� says communications consultant Laurie Brown.

Teleprompters 鈥� it鈥檚 so tempting for politicians to rely on them to help lighten the load of constant public speaking. But that can be dangerous, as figures from LBJ to Barack Obama and Sarah Palin have discovered.

Sure, go ahead and criticize. 鈥淯se a teleprompter? Faker! Inauthentic fraud!鈥� You try it. They are harder to use than they look.

Decoder mentions this because Mr. Obama uses them so often he鈥檚 been accused of needing them to talk to his family at dinner.

But look 鈥� Obama is just good at using them. Tele颅prompt颅ers have been in politics since ex-President Herbert Hoover used one to give the keynote at the 1952 GOP convention.

And if there is anyone who can give Obama a good game one-on-one when it comes to telepromptering, it鈥檚 Sarah Palin. She may have struggled in the interview with Katie Couric, but give her a speech text and a couple of screens to display the scrolling words, and she can get a GOP audience pumped.

As Ms. Palin recounts in her new book 鈥淕oing Rogue,鈥� as she gave her vice-presidential nomination acceptance speech at the Republican Convention 鈥� the biggest moment of her political life 鈥� her teleprompter malfunctioned, showing the wrong lines. She bought time by pointing and waving at some delegates wearing hockey-themed clothing.

Teleprompters were invented to help actors struggling to memorize soap opera lines. An operator controls the scrolling of text. Display screens can be placed over a camera, or on clear glass, or pretty much anywhere that gets speakers鈥� eyes up, so it doesn鈥檛 look as if they鈥檙e reading from a piece of paper.

Lots of politicians can鈥檛 use them. During the campaign, John McCain sounded as if he was reading from a grocery list he鈥檇 just found in his pocket.

Want three teleprompter tips from a pro? First, rehearse, rehearse, says Ms. Brown, who鈥檚 written a book on how to use teleprompters. Second, consult with the operators to make sure they know what you expect. Third, control the pace. If the words are going too fast, pause. The operator should stop.

Or not. In which case, you fire them.