Excerpt from this article:
Q. When did memes become a force in American politics?
A. The 2008 election was the light-bulb moment. Campaigns were trying to reach out to younger voters on emergent social media platforms like YouTube and Facebook. Shepard Fairey’s “Hope” poster went viral, inspired countless parodies and was an early breakthrough that shed a light on social media’s potential for crowdsourced campaigning.
So how did Pepe become a Trump symbol?
Pepe didn’t become political until Donald Trump endorsed it by retweeting a Trump version of the character, which led to a mass influx of pro-Trump Pepes.
You have to consider social media’s political climate leading up to 2016, which has been heavily marked by the gender war and identity politics. These things led to the emergence of a reactionary movement, namely the alt-right, and Trump was kind of the natural poster boy for that.
Pepe plugged into the ideology of the alt-right because it was a reaction against the people they call “normies.” Pepe had been a symbol of the disenfranchised, social outcasts. It was Trump’s natural audience.
Pretty soon there was a huge influx of racist Pepe memes from 4chan and The_Donald community on Reddit. But the real trigger point that led to mass production of Nazi and other offensive Pepes was after Hillary Clinton released a denouncement of the meme, which is a milestone in meme history.
No meme has ever been denounced by a presidential candidate. In a way, Pepe serves as a social media dog whistle for Trump followers to echo their implicit support of ultraconservative beliefs in public forums without risking the invitation of backlash.