The Wall Street Journal answers How the campaign season got so long.
American history is replete with examples of lengthy campaigns and multiyear chess games. Thomas Jefferson conducted a quiet effort against John Adams for the four years he was vice president to Adams, having lost a close Electoral College battle to him in 1796. Andrew Jackson never stopped running for president after he believed he was robbed of the office in 1824 by John Quincy Adams. Both these long-distance runners were rewarded with the White House.
What is novel, though, is the growing length of the overt public campaign for party nominations. For that we can largely thank Jimmy Carter.
Before 1976, extensive private preparations notwithstanding, candidates almost always waited until the actual calendar year of the election before announcing their candidacy. Mr. Carter changed that when he practically became a resident of Iowa, site of the country’s first nominating contest, shortly after he left office as governor of Georgia in 1975. His successful strategy became the new norm, copied by candidates in both parties since.
There’s also the nominating calendar:
From 1920 until 1972, the New Hampshire primary led off the presidential selection process on the second Tuesday in March. This helped to limit primary season to less than four months, until early June.
Then the great rush to the front of the primary pack began, fueled by states’ desires to get the money, media and electoral influence that come with early voting. In 1972, Florida tried to grab New Hampshire’s franchise, setting its primary for the same mid-March day as the Granite State’s. New Hampshire promptly moved up to March 7.
The leapfrogging has continued since and accelerated recently. In 1968, only New Hampshire held a March primary. By 1988 there were 20 March primaries. Inevitably, competition among states moved some of the March primaries into February, with a blizzard of 22 in February 2008.