Common issues arise, not just for those parties' leadership but all political parties. Leading the Nationals and the Greens has some similarities, but some important differences.

The Nationals' leadership is an enormous prize. If the Coalition is in office the occupant is immediately elevated to the position of Deputy Prime Minister. It enables that person to punch above their weight and/or ability. As the leader of the junior partner, the Nationals leader chooses the party's contingent in cabinet, including important ministerial positions generally with a rural and regional flavour.

They personally sign a confidential Coalition agreement with the Liberal prime minister which entrenches the priorities of the Nationals in Coalition policy. This agreement was a stone around Malcolm Turnbull's neck. As the more conservative of the two Coalition parties, the Nationals shore up the conservative wing of the Liberal Party, to the great frustration of moderate Liberals, on issues like energy policy, climate change and same-sex marriage, to name a few.

Being in Coalition brings great advantages but also great limitations to the Nationals. The parties are competitors in harness and the danger for the Nationals is that they become submerged and lose their own distinct identity, in so far as they still have one.

This is the context of Joyce's challenge. His own raw ambition and disgruntlement strikes a chord in the ranks of party members and MPs. The issue of "coalitionist versus stand-alone party" is a real and uncomfortable one which won't go away. It is magnified by the electoral threats from minor parties like One Nation and micro parties like the Shooters Fishers and Farmers, which can profess not to be tied up in Coalition red tape. To some country people the Nationals appear too domesticated when they want a feral voice free to openly criticise Liberal governments at the federal and state level.

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It also contributes to the continual splits and breakaways which dog the party. This happened at the time of the Turnbull-Morrison clash, when a couple of members moved to the crossbench temporarily. It also happened last week when Matt Canavan resigned from cabinet, and again this week when Llew O'Brien, having resigned from the Nationals, ended up as Deputy Speaker over the party's own choice.

The public discussion of the choice between McCormack and Joyce aired general matters of leadership style. In his early days in Parliament, when he was in the Senate, Joyce strained Coalition unity like many before him in the party. When Canavan made public his support for Joyce he said the party needed "a bulldog" and "a fighter" to defend coal jobs and cane farms. This was a direct criticism of McCormack and shows that the Nationals consider their enemies to also be within the Coalition itself - especially moderate Liberals - and not just the Labor opposition and the Greens.

Canavan's comments also raise matters of leadership style which apply to any political party. They are a natural bridge to talking about the leadership of the Greens. In some ways, while very different to McCormack, Di Natale was also at the quieter, more conciliatory end of the leadership scale. He revved himself up to a fever pitch of anger and indignation on occasions, but it was never his natural style. His successor Bandt, while very different to Joyce, is more of a bulldog. That was shown in his initial remarks after taking up his new job.

The Greens are very different to the Nationals, and not just in ideological position. They are about half the size in terms of parliamentary representation (10 to 21 MPs) but have a larger popular vote. They are a major voice for younger Australians. The new ANU Australian Election Study (AES) showed that a remarkable 28 per cent of those 34 and under voted Green last year. They are also largely a Senate party, and Bandt is their first leader to come from the House of Representatives and their only House of Representatives member.

Unlike the Nationals they are not a party of government at the federal level, and when they don't have a share in the Senate balance of power they are consigned to a weak position from which they must fight for influence. This is somewhat like being in perpetual opposition. For this reason Peter Garrett chose Labor over the Greens. Similarly, Cheryl Kernot left the Democrats for Labor because her party was frozen out.

The Greens, like the Nationals, are often fragmented and internally divided. They have suffered huge internal ructions in NSW and, to a lesser extent, in Victoria. One of the issues is the positioning of the party, including the balance between ecological issues and so-called "socialist" issues. What does it mean to be green? One job of the federal party leader is to try to keep everyone in the tent.

Like the Nationals, they are also dogged by an existential question of party identity. For the Greens it is the question of whether grassroots social-movement politics should sometimes take precedence over parliamentary politics. Given the limits of their parliamentary influence, that is a reasonable question.

Bandt will now be given time to settle in, but McCormack will constantly be looking over his shoulder. Past Green and Nationals leaders offer different models of how to perform the role. Some have been more like bulldogs, but most have not been. Watch to see how Bandt's style evolves and whether McCormack attempts to reinvent himself.