Assuming you’re talking about America, before 2000 votes were never closely scrutinized or thought of as fraudulent. In Florida there was the hanging chads thing in 2000, and a fringe clings to the idea that there was chicanery in 2004, perhaps in Ohio. But the 2008, 2012, and 2016 elections weren’t seized on as needing to be “investigated,” although the Republican candidate in 2016 declared that if he didn’t win the forthcoming election, it’d be due to widespread fraud and he might not accept the result. In 2020, that came to pass, with a clear and validated loss and he didn’t accept the result, infusing his supporters with the idea that there was massive fraud despite the lack of any evidence or verifiable documentation of it. Now, of course, we do have one party that seems perpetually trapped in a cycle of questioning all election outcomes that don’t align with their political goals, and it seems likely to only get worse.