I'm going to have a bit of a rant, because I see this a lot in this thread. If you, someone you know, or someone you merely watch says the line "The American people will forget everything" or any variation of that line. Know this makes you or them an idiot. Your/their view of the world is so utterly simplistic as to betray the fact you/they know -very- little about how people work.
Now that I am done personally attacking like, half this thread let me explain why.
The origins of this sentiment, like most, does have a kernel of truth. People can be stupidly forgiving of even major gaffes. The reason isn't that people are stupid, or sheeple, or whatever thing you have to say to make you feel personally superior. Largely, it boils down to three reasons, individually or any combination thereof. And I guarantee you do them too.
1: Everyone has their pet issues. Generally, 2-3 core issues that someone holds dear and focuses on to the exclusion of most else. They don't utterly ignore these issues, but these issues are the ones they consider -the- most important. The Left -really- invests in this one, and it's a good part of why they have a consistent vote. And they have worn away at it over time.
2: Just because you know it, doesn't mean everyone does. No, it's not their fault, it's yours. Most sane, healthy people don't spend their time on avian-themed websites which give them politics by the minute. They pick it up from their friends, their family, sometimes the news, sometimes their social media. In bits and pieces. Frankly, they are probably more well-adjusted than 99.9% of the people on this site, and the .1% who are better adjusted are feds. Still, this doesn't mean they 'forgot' or are 'sheeple' it just means they have lives to live and so don't really have the time or autism to go deeply digging into every single subject.
3: So we have focus on issues, and no time to look at everything. What does that leave? Simple, they just don't give a fuck. Interest in politics at large is a niche topic, it's depressing, probably shaving minutes, hours, even days off our lives. Often is messy, confusing, corrupt as fuck, and just plain unpleasant. There is a reason bread and circuses work, and its because people don't want to fucking deal with politics.
And the core takeaway of all of this? None of its permanent makes someone stupid or otherwise prevents them from remembering basic things. They do in fact remember, it's your job as someone who wants them to get angry over it to convince them to be so.