A four-year fixed parliamentary term will always look pretty good to the incumbents and pretty bad to the challengers. That's one reason this important constitutional reform for Australia has been so long talked about but never achieved. Now there is an opportunity for progress, after Opposition Leader Bill Shorten called for a cross-party push towards a referendum on it and Prime Minister Malcolm Turnbull seemed receptive to the idea.The two men have resolved to discuss it when next they meet.

The Herald has long backed a switch to four-year fixed terms. With non-fixed, three-year terms for the House of Representatives we are condemned to a perpetual election campaign, considering that the average life span of a federal government since 1910 has been only two and a half years. The ritual statement from defeated party leaders the day after an election – that their next campaign starts now – is not just rhetoric. While governments beholden to the 24/7 news cycle remain fixated on the next vote, long-term policymaking on complex issues looks too hard and too risky, and we end up with piecemeal but palatable change and fragile short-term fixes. There's not enough time to bed down big change, let alone get an idea of whether it's working, before the bells ring again for another bout at the ballot box. What else holds us back from much-needed changes to the tax system to increase fairness and efficiency? Why else are we still without an effective emissions trading mechanism or plausible policy on climate change?

When, as now, federal elections must be held within three years of a new parliament's first sitting but a prime minister can call an early election at almost any time, the incumbent can manipulate the electoral cycle to his or her party's advantage. There's also the cost pointed out by Coalition MP David Coleman, who has put forward a private members' bill: businesses and consumers tend to hold off on spending decisions during election periods and the "phoney war" that precedes them.

Britain recently introduced fixed five-year terms and most other countries have four- or five-year terms, often fixed, at no apparent cost to their democracies. Australia is one of very few advanced democratic nations stuck with three-year terms. All our states except Tasmania now have four-year fixed terms.

One problem is that under the constitution, a senator's term is twice that of a member of the lower house, but eight-year terms in the Senate would be too long. That is a significant stumbling block. One proposed solution is to reduce Senate terms to four years so all Senate seats fall vacant every election. Another problem is that we are well-advanced on a long, expensive and important process towards changing the constitution to give appropriate recognition to Indigenous Australians. The bar for a success at a referendum – a majority of voters nationally, and a majority of voters in a majority of states – is dauntingly high, and the conventional wisdom is that it's a bad idea to attempt too much at once.

Mr Turnbull and Mr Shorten have much to talk about. Their co-operation and leadership is essential if we are to find a path forward for the good of the nation.

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