Before Kamala Harris became the Democrats’ presumptive presidential nominee, discussions of a possible “landslide” victory for Donald Trump, though unlikely, were gaining traction. Surprisingly, current polls now show Harris leading. How did this shift happen?
One factor to consider is the absence of a true landslide in U.S. presidential elections since 1984, when Ronald Reagan defeated Walter Mondale by an overwhelming margin, winning 49 states. Reagan’s 18-point popular vote lead remains the last election decided by more than 10 points, a benchmark for a “landslide.”
Former President of the US, Donald Trump
While elections have been closer over the past 40 years, analyzing Reagan’s victory highlights the ongoing challenges pollsters face, especially when many voters remain undecided. Even in 1984, polls were not entirely accurate; some overstated or understated Reagan’s support, although they correctly predicted his win.
As Mondale’s campaign wound down in 1984, he dismissed polls showing him far behind, likening his situation to the infamous 1948 polling error where everyone expected Thomas E. Dewey to defeat President Harry Truman. Mondale even replicated Truman’s iconic moment of holding up a newspaper that prematurely declared Dewey the winner, emphasizing that voters, not polls, determine elections.
Despite Mondale’s confident rhetoric, the polls’ all in all message was clear—Reagan was set to win. However, the degree of his victory varied across polls, with some underestimating his support by huge margins.
This discrepancy underscores the persistent uncertainty pollsters face, particularly with late-deciding voters, a factor that played a crucial role in Trump’s 2016 victory in key states like Michigan, Pennsylvania, and Wisconsin.
