You have yet to document any confirmed occasions of fraud under mail-in-voting in any state impacting the outcome of an election.
[T]he nation’s Founding Fathers in drafting the Constitution gave authority over elections to the states, rather than the federal government...
State lawmakers approve the laws that govern the voting process in their states – and this can vary widely, depending on how they think elections should work...
Still, confusion about how elections are run and laws that differ from state to state helped fuel conspiracy theories still swirling today about the 2020 election, including the false claim that the presidential election was stolen.
In fact, there was no widespread fraud or tampering with the vote. And rules that differ don’t mean an election was inaccurate or that fraud occurred.
“While election laws and regulations differ from state to state, the common threads of bipartisanship, transparency and professionalism undergird the work of election administrators,” said Jennifer Morrell, a former election official in Utah and Colorado.
“In every state, policy makers are charged with creating the rules, election officials are responsible for carrying them out, and voters – regardless of party affiliation – are bound to them.”
How the US elects a president through thousands of local elections, with varying rules.
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If you believe Trump when he falsely tells you that he won the 2020 presidential election "in a LANDSLIDE!," please cite the instances of voter fraud that have been confirmed.