The current state-by-state winner-take-all method of electing the President starts by dividing America’s 158,000,000 voters into 51 state-level elections.
The result of breaking the country into 51 separate elections is that the Presidency is frequently decided by a few thousand votes in a handful of states.
Real or imagined irregularities regularly invite hair-splitting legal disputes, recounts, and loss of confidence in elections. This was the dynamic that led to the January 6, 2021 riot.
The first-place presidential candidate had an average lead of 4.7 million votes in the last six elections.
But the current state-by-state system repeatedly creates uncertainty and the opportunity for unnecessary recounts, lawsuits, and doubt. If 5,229 voters in Arizona, 5,890 in Georgia, and 10,342 in Wisconsin changed their minds in 2020, Joe Biden would have been defeated -- despite leading nationally by over 7,000,000 votes.
Similarly, in 2004, had 59,393 voters in Ohio changed their minds, President Bush would have lost, despite leading the national popular vote by over 3 million votes.
The fragility of the current state-by-state system is illustrated by the fact that we have had two near-misses in the Electoral College in the last six presidential elections (2020 and 2004). And, in the candidate who lost the nationwide vote became President in two other elections (2016 and 2000).
More info