Can you recall the last time anyone besides a Democrat or a Republican was elected president of the United States? It last happened in 1848, when Zachary Taylor, the great hero of the Mexican War, swept to the White House as the Whig Party candidate, defeating Democrat Lewis Cass.


A century later, in the presidential election of 1948, the Democrats and Republicans faced opposition not only from a major "third-party" candidate, but from an equally powerful "fourth-party" contender as well. This unusual situation resulted from the fracturing of the Democratic Party.


When the party nominated President Harry S. Truman at its convention in July, Southern Democrats opposed to Truman’s civil rights program walked out and formed their own group, the States’ Rights Democratic Party. Popularly known as the "Dixiecrats," these conservative Democrats chose South Carolina Gov. Strom Thurmond as their candidate. Meanwhile, many liberal Democrats had also deserted to the new Progressive Party and its candidate, former Vice president Henry A. Wallace, whose campaign was based on opposition to Truman’s Cold War policies against the Soviet Union.


With both its right and left wings missing, no one expected the Democratic ticket to get off the ground. Confident of victory, New York Gov. Thomas E. Dewey, the Republican candidate, conducted a bland campaign in which he tried to avoid saying anything controversial. He was confirmed in this strategy by polls showing him with a sizable lead over Truman.


Most observers were certain the defection of the Dixiecrats and the Progressives would deprive Truman of the Democratic "Solid South" as well as the urban vote Democrats needed to carry the large Northern industrial states.


Of course, everyone knows what happened: Truman’s upset victory is one of the greatest stories in American political history. He waged a rip-roaring, aggressive campaign that contrasted favorably with Dewey’s tepid effort. As an old-fashioned politician, Truman also had little faith in opinion polls.


Trusting too much in their own data and supposed infallibility, the pollsters failed to conduct surveys during the final days of the campaign and missed a dramatic late shift in Truman’s favor, particularly among undecided voters.


But that election also demonstrated once again the inability of "third parties" to mount a serious challenge to the Democratic-Republican two-party system that has prevailed in the United States since the 1850s. In 1948, Thurmond and Wallace each received only about 2.4 percent of the popular vote. Thurmond won 39 votes in the Electoral College; Wallace received none. Thurmond’s candidacy probably cost Truman the support of four states in the Deep South, while Wallace may have taken enough votes away from Truman to ensure a Dewey victory in New York. But these defections did not prevent Truman from winning the election.


Since the 1850s, only two third-party candidates have received more than 20 percent of the popular vote in a presidential election. Both were former presidents trying to return to the White House: Millard Fillmore with the American Party in 1856 and Theodore Roosevelt as the "Bull Moose" Party’s candidate in 1912. Neither came close to winning. More recently, H. Ross Perot mounted strong third-party campaigns in 1992 and 1996 but failed to carry a single state.


However, third-party votes have sometimes been crucial in determining the winner of close presidential elections – and this was true in 1948 as well. Wallace almost took enough votes away from Truman in Ohio and California to throw those two crucial states into the Republican column. This would have denied Truman a majority in the Electoral College and left it to the House of Representatives to select the next president.


If you’re interested in the 1948 election, please visit the museum at the Harry S. Truman Library when it reopens this fall. Also, you can explore the documents and other resources that are located on our website at https://www.trumanlibrary.gov/library/online-collections/1948-election-campaign.


– Randy Sowell is an archivist at the Truman Library.