In The American Scholar, Christopher Clausen investigates the phrase that comes ‘round and ‘round. He starts in July 1864, when Lincoln was running for a second term against Gen. George B. McClellan, three years into the Civil War. A New York Times editorial that year stated: “We have had many important elections, but never one so important as that now approaching….The republic is approaching what is to be one of the most important elections in its history.”
A few more iterations, courtesy of Clausen:
As the republic’s history lengthened, the phrase often mutated into “the most important election in my lifetime” or “in a century.” Still, in all its forms it proved remarkably resistant to irony or derision. In 1988, when George H. W. Bush ran against Michael Dukakis, the already venerable Senator Robert C. Byrd declared: “It may be the most important election of this century.” In 1992, when Bush ran for re-election against Bill Clinton, Clinton declared it “the most important election in a generation,” generation being a word that sounds weighty and biblical but is often deployed without any precise meaning.
By 1996, when Clinton himself was running for a second term against Senator Robert Dole, Ralph Reed, executive director of the Christian Coalition, declared it “the most important election of our lifetime,” while John Sweeney, president of the AFL-CIO, pushed the envelope by describing it as “the most critical election in the long history of the American labor movement.” In November 2000 Ebony magazine tried to re-establish a sense of proportion by asserting, “The first national election of the 21st century is the most important election (so far) of the 21st century,” though strictly speaking it was still the 20th. By 2004 everyone was getting in on the act, from the rock band Pearl Jam (“the most important [election] of our lifetime”) to Bruce Springsteen and Democratic nominee John Kerry (“the most important election of our lifetime”) to the Christian Coalition again (“the most important election in our nation’s history”).