I always hate the "time traveller kills Hitler" stchick.
Killing Reagan does not change the political climate that allowed him to rise to power. In fact killing him could have made things worse for the USA. See 9/11 for a recent example.
I wouldn't have killed Regan had I gone back in time, I would've gone a bit further back and after Rockerfeller got forced to sell standard oil, I would've offed him just before he was able to use the money he gained to form Chicago University and it's dreaded Chicago school of economics.(home to the ludicrous idea that the free market will regulate itself) Which I think had even worse consequences than Reganomics, if not directly influencing it.
At the very least, it would've likely extended the 30 years worth of post Roosevelt economic prosperity that decreased wage gaps, and actively created the middle class at least a bit longer before some other rich butthole got the same or a similar idea as Rockerfeller.
It's called the University of Chicago. And yup, it continues to be a vicious pile of shit to this day, fucking over the vulnerable communities around it, providing substandard health care and sitting on a 10 billion dollar endowment that they refuse to use to either raise employee wages or lower tuition. (Fun fact: They're projected to become the first university in the country to have six-figure tuition.)
The problem isn't even free market concepts, it's the idea that you can advocate for a free market in a highly regulated country. When the definition of corporation is controlled and liability is removed from individuals you can't have a free market.
That assumes you're only pulling off one time-travel assassination. What if you just keep doing them until the lack of the relevant people shifts the political climate by itself? Like in the "go back and kill Hitler (or just push him onto a different life path at a young age, if you have time travel, you can probably remove someone as a leader without just killing them), sure, maybe a different fascist rises in Germany instead, but if you take out that one too, and the next one, and the next, eventually someone who isn't a fascist will manage to get into office, or if you keep it up long enough, the german fascist movement will run out of viable leaders, and cease to be a major factor in the political climate of the time.
To be honest, going back and just taking Hitler or any similarly historically important person out of the equation is likely enough to do that, for most people, given the impact he had on the world, or at the least removes the reason for you to go back in time, so presumably if you're seriously contemplating doing this, whatever time travel mechanism you have going on probably has to be one where you are shielded from the consequences of whatever changes you make anyway.
If time travel is possible, and it isn't the "going to another universe" kind, then it would be impossible to do anything that would cause a paradox. You exist in the timeline, therefore any attempts to change that have failed/will fail.
Killing Reagan does not change the political climate that allowed him to rise to power
You're both right and wrong. While it wouldn't change the circumstances that led to his election directly, he himself played a big part in CREATING those circumstances and perpetuating them to the point of the Trump cult eventually becoming all but inevitable.
Who knows? Maybe if we got rid of Reagan early enough, Bush the elder would work towards the "open borders" he argued for during the primary debate against him.
That's just one of dozens if not hundreds of issues where Bush the elder becoming potus earlier would, while not great, be much preferable to 8 years of Reagan. Hell, who knows? Might have made a more left wing candidate than Clinton the next president!
PS: everyone seems to be forgetting that, on top of his OWN bad policy choices, the country was pretty much run by the throat goat drug demonizer Nancy and his favorite astrologer towards the end where the dementia had made him incapable of doing much himself.
I just had the same thought, then went down an entire rabbit hole of who would actually be too blame. You're basically looking at social evolution, over millions of years, and trying to find the "start". It's impossible. Pick a spot, and pull.