Former President Donald Trump in 2016 won one of the biggest upsets in American political history by squeezing out just enough votes in key Electoral College states. Trump's victory over Democratic rival Hillary Clinton was decided by about 77,000 votes out of 136 million ballots cast. He won Pennsylvania by 0.7 percentage points (44,292 votes), Wisconsin by 0.7 points (22,748 votes), and Michigan by 0.2 points (10,704 votes).
Four years later, President Joe Biden evicted Trump from the White House by stitching together narrow margins of victory in a handful of states despite winning the popular vote by nearly 7 million. Just 44,000 votes in Georgia, Arizona, and Wisconsin separated Biden and Trump from a 269-269 Electoral College tie, which likely would have meant the GOP incumbent's reelection.
Arizona — 11 electoral votes
The Grand Canyon State was once such a Republican stronghold that from 1952 to 2016, only a single Democratic nominee won its electoral votes, President Bill Clinton, in his 1996 reelection. But shifting demographics and rapid population growth have changed Arizona's political complexion.