The devastation won't reach 'Known Space' for thousands of years, but the alien Puppeteers that funded the trip are paranoid herbivores. They immediately start a mass exodus of their whole species out of the galaxy, causing a massive economic crash along with many effects on other plot lines.
Niven's Known Space future (and past) history is an amazing and incredibly influential achievement. Highly recommended. Most of it consists of collections of short stories and novellas written over decades, so it's very digestible.
If only Spiro T. Agnew would have made it.
I suspect that Niven and Fillmore have roughly equal name recognition, though, simply by the nature that Niven is still alive, and appears to be more consequential long term.
https://gatherer.wizards.com/Pages/Card/Details.aspx?multive...
(It would be interesting if he ever wrote the story set in this universe, after the modern times, in which humanity gets out to space, and, uh, hey guyz, magic kinda... works out here... what the heck? It wouldn't necessarily take long to figure out what the deal is with Earth being a dead zone, but it would cause some interesting political upheaval as suddenly the sparse space colonies that nobody thought were worth anything and barely even worth the effort became industrial powerhouses as the only place where magic works... and not just the tame, dying magic of Niven's stories, but the original wild, abundant magic the stories claimed Earth initially had.)
Being outside the US I never covered past US presidents in school.
"Jerry Pournelle named Bureaucracy as his game of the month for October 1987, stating that he and Larry Niven became "engrossed""
1: https://en.wikipedia.org/wiki/Fillmore_District,_San_Francis...