There are a number of ways to evaluate the biggest win in the history of American presidential elections. You can take the simple figure of who won the most actual votes; who won the largest percentage of the vote; who took the largest share of the vote; or who won the most electoral college votes -- the latter being the method actually used to elect the president.
Largest Percentage of Vote
Lyndon Johnson may have only entered the Oval Office by inheriting John F. Kennedy’s office after his assassination in 1963, but he won a full term in emphatic fashion in the 1964 presidential election. Running against Republican Barry Goldwater, Johnson won 61.1 percent of the popular vote, dwarfing Goldwater’s 38.5.
This was the largest percentage of the vote that any presidential candidate has won in a contested election -- although it should be noted that George Washington’s wins in 1789 and 1792 and James Monroe’s 1820 victory were technically all margins of 100 percent, as they effectively ran unopposed.
Largest Share of the Vote
The most lopsided election in American political history in terms of percentage of the vote was the 1936 presidential race between incumbent Franklin D. Roosevelt and Kansas governor, Alf Landon.
Roosevelt won 60.8 percent of the vote compared to Landon’s 36.5, a disparity of 24.4 percent. Roosevelt’s popularity was so great that went on to become the only president to be elected to four terms, although he died shortly after his fourth electoral win in 1944. The 22nd Amendment was introduced after his death to formalize the convention that presidents can only serve two terms.
Largest Number of Votes
In simple terms of who won the most votes, Richard Nixon’s 1972 defeat of George McGovern stands out. Incumbent Nixon won every state save Massachusetts, garnering 47 million votes, while McGovern took 29 million -- a difference of 18 million votes. This was the largest win in the popular vote in American electoral history.
This represented Nixon with 60.7 percent of the vote and McGovern with just 37.5 -- itself the fourth-largest percentage margin in electoral history.
Largest Number of Electoral Votes
In the presidential-election system, each state carries a certain amount of weight, depending on population, which is represented by “electoral votes." A large state like California has 55, as of 2011, while a smaller state like South Dakota has only three.
After winning the presidency from incumbent Jimmy Carter in 1980, Ronald Reagan won his second term in 1984 in a landslide win over Democrat Walter Mondale. Mondale only won the District of Columbia and his home state of Minnesota, giving him a mere 13 electoral votes -- Reagan, carrying the other 49 states, took 525, the highest total ever achieved by a candidate.