If you have not read 1984, I suggest you do so. The movie doesn't actually do it justice, in my opinion.
As I recall, there was something the book described as the Ministry of Truth, where history was erased and replaced on a daily basis according to the whim of Big Brother.
We have been there since the first time it was elected.
1984 is one my favorite books.
Very basic breakdown of the world for those that don't know: there are three super states in the world. Oceania (where the story takes place, specifically London), which comprises of the British Isles, Australia/New Zealand and North/South America, including the Caribbean, Eurasia which comprises of entirety of Europe including Russia, and Eastasia, comprising of China, Japan, Korea, and the rest of that region.
The three super states are locked in a permanent war where it's always 2 vs 1, and alliances shift constantly. They're presumably fighting over resources in Africa and the Middle East/Central Asia, who are not part of these or any superstate. Why this war is neverending is a mystery, until you get to the latter half of the story. The thing is, all three states are totalitarian, who seek to have complete control over their populations, or at least what we're led to believe about them anyway. And by complete control, that means controlling ones perception of reality.
Like the poster above mentioned, in Oceania there are different ministries that deal with the particulars of government, with the protagonist of the story working at the Ministry of Truth, which deals with propoganda. See in order for the government to maintain complete control, they have to be seen as never being in the wrong. Which means that if they switch alliances between the other two superstates, the Ministry of Truth is there to scrub and rewrite all or the media to make it such that they government was always always allied with whoever they're allied with today.
*Slight spoiler*
My favorite part is when they're at the Hate Week rally, and some guy is giving a speech about how evil Eastasia is as the enemy, and while he's talking, something walks on stage, whispers in his ear, and without even pausing for a second, switches his language to demonizing Eurasia as the enemy. The crowd is stunned, not because the speaker suddenly switched who the enemy was, but because somehow, the enemy managed to sneak in and change the names on the banners (that those same people had put up btw) to an allied state! Do that actually believe this? No, but they do so out of lying to themselves and fear of being called out for not supporting the party, which can get them disappeared.
Whenever I see Maga switch up their supposed positions on things as long a Trump says so, it reminds me a lot about that scene.