Realigning Election: An election during periods of expanded suffrage and change in the economy and society that proves to be a turning point, redefining the agenda of politics and the alignment of voters within parties. This can also be known as a key election or critical election. Our party system has been shaped by these elections which have taken place roughly every generation or 32 years. 1824: Andrew Jackson & the Democrats; 1860: Civil War Republicans; 1886: Republican Progressives; 1932: FDR's New Deal. Check out all the U.S. presidential election maps ever.
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Judging by the patterns of US history, it is most likely that there has been a realigning election since 1932, where new factions and party members coalesced into a majority force in politics.