Has any major national election ever been proven fraudulent? The most widely publicized election fraud examples, usually but not always coming from openly desp

Has any major national election ever been proven fraudulent? The most widely publicized election fraud examples, usually but not always coming from openly despotic regimes, never are proven per se. They are just accepted as fraud by the international community because the results are unlikely. (Eg putin got 100% of the votes.) To be clear, I’d never claim America has election fraud. It’s a dangerous claim to make, and not just in despotic regimes. It’s the proverbial crying wolf.