In Fahrenheit 451, how does the government use propaganda to manipulate the opinions of the people?
One good example of the propaganda techniques used in Fahrenheit 451 comes when Montag is pursued by the government for killing Chief Beatty. When he successfully escapes the city, the government uses the media and the television, which has programmed civilians to have short attention spans and no curiosity, to show Montag being killed even though he is long gone:
"They're faking. You threw them off at the river. They can't admit it. They know they can hold their audience only so long. The show's got to have a snap ending, quick... So they're sniffing for a scape-goat to end things with a bang."
(Bradbury, Fahrenheit 451, Google Books)
Here, the possibility of Montag as a revolutionary figure is dangerous, so it is vital to remove him from the public perception as fast as possible. By showing a fictionalized, controlled chase on TV (much like the scripted "reality" TV of today) the government is able to show their efficiency and power in destroying seditious behavior. TV is used to both control the population, and to spread government-approved "truth," regardless of the actual events.
The most clear way the government uses propaganda to manipulate people's opinions is by burning books. This directly destroys a vast amount of information: from literature to philosophical works to texts on government policies. And these texts, works, and policies certainly include ideas which would contradict the propaganda of the ruling government. So, in this way, the government destroys any potential propaganda which might oppose their own propaganda. By eliminating any opposition, the people are only left with the government's propaganda.
The symbolic 451 on the firemen's helmets serves to reinforce the idea that burning books is for the public good. When people see firemen, even in the world of Fahrenheit 451, they think of a protective force, an institution designed to make people safe. Combining that with the notion of burning books, symbolized by the "451," the government reinforces the idea that burning books is for the greater good. This is propaganda in the form of a symbol (451): similar to the way nations encourage patriotism or nationalism with flags, mottoes, symbols, crests, etc.
Another use of propaganda is the firemen's code, absurdly (to the reader) misapplied as the words of Benjamin Franklin (who actually was involved in the founding of the first fire department):
"Established, 1790, to burn English-influenced books in the Colonies. First Fireman: Benjamin Franklin."
RULE 1. Answer the alarm swiftly.
2. Start the fire swiftly.
3. Burn everything.
4. Report back to firehouse immediately.
5. Stand alert for other alarms
This is noted right after Montag boldly asks Beatty and other firemen if previous firemen used to put fires out. Obviously, the current government and fire departments have taken historical records (that of Franklin's involvement with early fire departments) and twisted the historical records to suit their propaganda.