This the fifth in a series of stories comparing the U.S. system of politics and elections with other democracies around the world.

Minnesota held a statewide primary on Aug. 12.

The marquee contest, for the Republican nomination for governor, was fairly close and exciting, with the top four candidates each getting more than 20 percent of the vote. Hennepin County Commissioner Jeff Johnson (who also had the endorsement of the Republican convention) won by a solid-but-not-huge margin with 30 percent of the vote, but…

… that was 30 percent of a staggeringly low overall turnout of 10 percent of eligible voters.

(The 10 percent turnout was not a record low nor an anomaly. In the 2012 primary, it was 9.28 percent. In 2004: 7.73 percent. )

So this year, 30 percent of 10 percent — or about 3 percent — of eligible voters decided the most consequential race of the primary season in Minnesota, a state that regularly leads the nation in voter participation on general election days.

(Just to clarify: The total turnout for the primary was 10 percent of the Minnesota electorate. Fewer than half of those voters even voted in the race for the Republican nomination because they most of them voted in either the Democratic or Independence Party primaries. That is, of course, reasonable and natural in a primary. But the overall point stands. Primaries can make very consequential decisions with very few voters, not because the races are close but because the vast majority of the electorate doesn’t vote in primaries.)

Primaries and other nations

Primaries. We’re so used to hearing about them (although not particularly used to voting in them). But it turns out that when you apply a prism of international comparisons among democracies, primaries are another way that the U.S. political system differs from all other world democracies. Most of the others don’t have primaries at all. None of them rely so heavily on primaries.

In our system, primaries generally are used to nominate candidates, not only for president, Congress and statewide offices (in Minnesota we’ve got that list down to four offices — not counting judges — but in Texas, for example, they also still elect an agriculture commissioner and a railroad commission), but also for county and municipal offices.

All of these are susceptible to primary elections, which are almost universally decided by a small portion of the electorate — much, much smaller than the typical 60 percent that characterizes presidential elections. And in some of those down-ballot races, the primary voter is often confronted with a choice between two or three names they’ve never seen before who may differ on issues the voter has never imagined for an office the function of which the voter cannot describe. (Note that Minneapolis and St. Paul, which have adopted Ranked Choice Voting, no longer have primaries for municipal offices.)

In other democracies, parties use an internal process, dominated by party leaders, elected party officials or, in some cases, a fairly small group of card-carrying, dues-paying members to choose their nominees. The larger public doesn’t get involved until general election day (which they don’t have to call “general election day” because there is no other election day).

The United States used to use the same basic system. Primaries arose in the late 19th and early 20th centuries as a reaction against the system being too dominated by insiders and party bosses.

Minnesota was, by the way, among the leaders in the creation of the primary election. According to ACE: The Electoral Knowledge Networks, “The first statewide primary was held 1899 in Minnesota. Two years later, Minnesota instituted the first mandatory statewide primary system,” although I gather in some versions of the history, Wisconsin had a couple of important firsts.

Progressive Era ‘reform’

Anyway, the primary was one of those Progressive Era “reforms.” And if you look at it in the “corrupt party boss” era in which it emerged, it sounds like a good idea. And maybe it is.

But tied to the super-low turnouts, the primary system has some odd, troubling effects, the most famous of this year was the defeat — by a small margin in a low-turnout primary in one congressional district of Virginia — of Eric Cantor. Cantor was, of course, the majority leader of the U.S. House and, as such, a high-ranking leader of both the U.S. House and the national Republican Party. He represented a reliably Republican district. He likely could have stayed in Congress as long as he wanted and perhaps become speaker of the House, if all he had to do was beat the Democratic nominee every two years.

But this year, he faced a primary challenge from the right, by David Brat, a Tea Party favorite, who stunned the world by beating Cantor in the primary by 7,200 votes. (Brat’s Minnesota connection noted here.) That makes a solid 11-percentage-point margin, and the primary actually had an unusually high turnout compared to recent Virginia primaries. In fact, the turnout was so high that some analysts believe Brat was helped my mischievous Democrats crossing over and voting in the Republican primary (which, if it happened, would be legal, if not exactly cricket, under rules governing primary voting in Virginia).

But this surprisingly large turnout was still just 13.7 of eligible voters. An observer from another democracy would likely find it strange that a politician holding such a high-ranking position of the majority party in the House and a likely future speaker could be removed from politics by so few people of no special public or party rank.

I don’t mean to portray it as any kind of tragedy. Brat won fair and square. Cantor has already fallen up into a much higher-paying job on Wall Street. He was seamlessly replaced as speaker-in-waiting by a very similar Republican.

Political Scientist Steven L. Taylor, a lead author of one of the comparative democracy textbooks on which I’ve been relying, put the problem this way: “The U.S. system of primaries shifts an awful lot of leverage to a very small primary electorate,” and, for the most part, shifts it away from the larger electorate and away from the political parties and their leaders.

Over recent cycles, this has strengthened the extreme factions — especially within the dynamics of the Republican Party — and reinforced some of the gridlock that has characterized recent sessions of Congress.

“A member of Congress is deeply beholden to whoever has the power to nominate him for another term,” Taylor said. In other systems, that’s the party leadership. In the American system “that’s the primary voter,” Taylor said.

Changes incentive

You’ve seen this analysis before, but now think about it in the context of how our system — in this case, the single-member district, the preponderance of “safe seats,” the reliance on primaries, the low turnout — changes the incentive for a member to think about how to best secure his or her political future, especially in the current political circumstance of a Republican member.

If he or she has a “safe seat” — as Cantor did, and as most U.S. House members do – that representative has little to worry about from the next Democratic challenger. “There’s very little [House Speaker] John Boehner can do to punish him,” Taylor said. “For a lot of members, the biggest worry is being ‘primaried.’”

Recent history suggests the primary challenge a GOP member of Congress worries about will come from the right, fueled by the no-compromise enthusiasm of the Tea Party movement, sometimes fused with the ideological purity of the party’s Liberty wing.

In the 2012 election, several of those challengers — especially for Senate seats — succeeded in defeating incumbents, often based on the argument that the incumbent had engaged in too many compromises with big-government Democrats.

This year, most incumbents facing such challenges survived — with Cantor as the biggest exception. But what did they do to survive? Taylor argues that in today’s climate, many of the incentives are to move right, even — perhaps especially — on those big showdown votes over a compromise to pass a budget that will keep the government open or even a must-pass vote to raise the debt ceiling in order to preserve the government’s credit rating.

I’m sure it’s possible to argue that as long as all the voters have a reasonable opportunity to vote, it’s no sin to allow the electorate to choose the nominees. And it’s hard to get excited about transferring power from the electorate (even a small portion of it) to anything that can be described as the party bosses. But Taylor’s analysis raises the question of whether the American devotion to primaries is helping our democracy function. Certainly the rest of the democratic world, with the opportunity to observe how we nominate general-election candidates, has decided to go in another direction.

Because this isn’t a presidential election year, I haven’t spent much time here on the long, winding process of primaries (and, in some states, caucuses) to choose the nominees for president (although technically what we choose in those primaries are delegations to the national party conventions, which ratify the presidential nominations, but, since the 1960s, the nominees have always been the winners of the primary process).

That process is full of truly bizarre features, like the one that assigns two states (Iowa and New Hampshire) a permanent oversized role in the sorting out of the field. Like many features of our system, we’re so used to it that we have trouble grasping how strange that is. There’s nothing else in the world remotely like it.