Does America’s primary system benefit extreme candidates?

AMERICA’S WAY of choosing candidates for general elections is unique. The primary system—in which a vote, usually among party members, decides which politicians are nominated—gives the public unusual power. So far this year, Republican primary voters have chosen candidates with views that, until recently, would have seemed extreme. In Arizona they opted for a slate of nominees who deny the result of the 2020 presidential election. In Pennsylvania’s gubernatorial race, they picked a candidate who was at the Capitol riot on January 6th 2021 (though he claims he did not enter the building). On August 16th voters in Wyoming rejected Liz Cheney, once the third highest ranking Republican in the House of Representatives, now—to the disgust of most of her party mates in Congress—a leader of the House committee investigating the events of January 6th. Do moderates suffer because of the primary system?

America’s constitution does not require primaries. Until the early 20th century they were not widespread. Candidates were instead chosen by rowdy in-person caucuses, where shouting the loudest—or an endorsement from party leaders—was the surest route to success. (Iowa and Wyoming still use caucuses to select presidential candidates.) The system became a target for reformers, who wanted to get nominating power away “from the machine, which can and often is purchased, to the people,” in the words of the Outlook, a progressive weekly, in 1898. Primaries soon became a way to exclude as well as to empower voters. Several southern states allowed only white voters to participate, a system that was not declared unconstitutional until 1944. Since the second world war, primaries have become more significant. By 1958, every state held one for at least some elected offices, from Washington senators to the state attorney-general.

Primaries tend to have a lower turn-out than general elections. Some fear that activist voters from the fringes of the two main parties have an outsize effect, pulling candidates away from the centre. But political scientists have found little evidence of this. Primary voters are more likely to follow politics closely, but tend to be reasonably representative of both general-election voters and those who identify as Democrats or Republicans. In one paper from 2018, voters scored themselves on a five-point scale, from “very liberal” to “very conservative”. Republican primary voters were only about 0.2 points more conservative than Republican general-election voters. For Democrats, the difference was even smaller—roughly 0.1.

Other researchers have occasionally found that extreme views give candidates a slight edge; but the advantage is cancelled out in the general election, when their opponent benefits from looking comparatively moderate. Centrists struggle in primaries because America has become more polarised, not because the system has aided that shift. This year, for example, candidates that support the Big Lie of election fraud in 2020 have done well in Republican primaries because most Republicans share their belief.

Almost half of states have opened their primaries to independent voters, but there is little evidence that these places pick less-extreme candidates. California and Washington run “jungle primaries” of Democrats and Republicans and send the top two candidates to the general election regardless of party affiliation. But that does not seem to pull politicians to the centre either. Even returning the choice to the “smoke-filled rooms” of the pre-primary age would not necessarily help. “The party organisations are probably at least as captured, if not more, by extremists than the primary electorates,” says Andrew Hall, a political scientist at Stanford University. Party elites certainly offered no sanctuary to Ms Cheney; last May, she was ousted from her House leadership position by her fellow Republican lawmakers. Primary voters followed their lead. ■

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