History and impact - What is Super Tuesday?

Super Tuesday is the first day in which the U.S. presidential candidates will participate in a primary that includes 12 states. Prior to this, the candidates campaign one state at a time, with the field of candidates shrinking as the process moves along. Super Tuesday provides the remaining candidates a chance to win multiple states and many delegates to the party’s nominating convention – the official scorecard by which a race is actually won.

To understand how this day came about, let's back up to how the United States picks its candidates. Every four years, the entire country goes to the polls the first Tuesday in November to decide who the country wants to be its next president, usually picking between one member of the Republican Party and one from the Democratic Party.

But each party picks its candidate in a series of state by state elections. Those are held on various days throughout the winter and spring of the election year.

Why voting on a Tuesday?
 

Most Americans agree that the earlier their state gets to vote in the process, the better chance they have of influencing who will eventually win their respective party's nomination. A mix of tradition and politics has kept Iowa and New Hampshire at the front of America's primary process for 40-plus years. But there's no rule that each state's voting has to fall on different days, so a significantly large group of states has settled on one particular Tuesday about a month into the primary season, known as Super Tuesday.

The phrase Super Tuesday was used in newspaper articles as far back as 1976. The reason Americans tend to vote on Tuesdays goes back even further, to the mid-19th century, when Congress decided the day made the most sense when getting people to travel from their rural homes into a town to vote.

But most people agree that, when Super Tuesday does come around, it traditionally marks presidential candidates' biggest challenge -- or opportunity -- to date. Up until Super Tuesday in the 2016 nominating contest, the potential nominees will have battled it out in just four states (Iowa, New Hampshire, South Carolina and Nevada) -- each state on a different day and each state with its own unique politics, traditions and demographics. On Super Tuesday, the candidates have a chance to prove they can win in three times as many states, all at once. In that way, it’s much more akin to the final Election Day in November.

Super Tuesday can change the entire race
 

Super Tuesday's impact on the race depends on how many candidates are still in it by that point. Often, it can reinforce that the leading candidates won’t be beaten, and many a candidate has clinched their respective party's nomination after a strong showing on Super Tuesday.

But a surprise finish by someone on Super Tuesday can change the entire race. In 1992, Bill Clinton had struggled in earlier nominating states but won many Southern states convincingly on Super Tuesday, prompting some pundits to declare him "back from the dead." He went on to win the Democratic nomination and eventually the presidency.

Super Tuesday usually falls in early March, but it doesn't necessarily fall on the same Tuesday every time. This year, it's on March 1. Fourteen states representing a quarter of the U.S. electorate, stretching from New England to the South to the West, will hold primaries or caucuses on this day.

The importance of March 15

Super Tuesday is the biggest one-day nominating contest in the primary season. But don't tune out of the presidential race after that. Some non-partisan political watchers argue there's another Tuesday in March that might be more politically meaningful. Two weeks later, on March 15, five states from the Midwest to the Southeast will vote. Demographically, these states tend to reflect the U.S.'s national voter profile -- a mix of urban and rural communities, a mix of college-educated, working class and increasingly diverse voters -- more accurately than those states that vote on this year's Super Tuesday.

Either way, by mid-March, the 2016 presidential nominating contest on both sides will be halfway done. Some 60 percent of the U.S. electorate will have had the opportunity to cast votes, and about 50 percent of delegates will have been decided.

This text was published within a cooperation with Washington Post.