America’s long, drawn-out election season continues, with primary elections in 11 states yesterday (Australian time) to choose candidates for state and congressional elections on November 2. But whereas the last big primary day, three weeks ago showed notable swings against incumbents and establishment candidates, yesterday’s results are more equivocal.

Probably the biggest insurgent victory was in Nevada, where Sharron Angle, a favorite of the tea party movement, convincingly won the Republican nomination for senator. She will now face off against Democrat Senate leader Harry Reid; Reid has been trailing badly in the polls, but having such a non-mainstream candidate as an opponent will give him a much-needed boost.

In other races, however, the mainstream candidates didn’t do too badly.

Incumbent senator Blanche Lincoln won her Democratic primary runoff in Arkansas, holding off a challenge from the Left, and Republicans in California endorsed two relatively centrist women: eBay billionaire Meg Whitman for governor, to succeed Arnold Schwarzenegger, and Carly Fiorina, former head of Hewlett-Packard, for senator.

Most interesting, however, was Californians other reaction to their dysfunctional government. By a vote of 54% they approved proposition 14, a measure to introduce non-partisan blanket primaries — also called “jungle primaries” — for state and congressional elections.

In a regular primary system, each party’s candidates are chosen in separate primary ballots, and then run against each other in the general election (together with whatever minor party candidates can get on the ballot). But in a jungle primary (used for many years in Louisiana and recently introduced in Washington state), everyone runs together in one primary, and the two candidates with the most votes — regardless of which party they’re from, and even if they’re both from the same party — contest the general election.

The effect is to establish a system very like a two-round election; the primary ceases to be in any meaningful sense a “party” election and becomes just the first round of the general election. If one candidate gets more than 50%, no further vote is necessary, otherwise the top two fight it out in a runoff. But whereas in a two-round election the gap between rounds is typically from one to four weeks, in California, unless they change the calendar, it will be five months.

At the other end of the scale, in Australia, we run this sort of system with no gap at all — “instant run-off” voting, as the Americans label our preferential system. Our way of doing it not only saves the cost of two separate elections, but also allows the possibility that someone who doesn’t finish in the top two can still get up with a strong enough preference flow.

Advocates of the jungle primary argue that it will eliminate the problem of primary candidates catering to the extremists in both parties, leading to more moderate representation and less deadlock in government.

The proposal was opposed by the party hierarchies, but strongly backed by Schwarzenegger and his coterie of moderate Republicans.

Some have fingered California’s propensity to enact sweeping reforms by referendum as part of what has made the state ungovernable. But this looks like a case of voters making a serious attempt to address the structural problems in their political system — much as New Zealanders did some years ago with the introduction of proportional representation.

It may be just a passing fad, but if this becomes a serious trend it could produce some big changes in US politics.