The modern Liberal Party now contains deeper and wider ideological divisions than the Labor Party. This will be true regardless of who emerges as leader today. This is a relatively new development but it has been building for two or three decades at least.
That is the prime cause of the current party troubles. There are other factors too. There is a question mark over Malcolm Turnbull's leadership qualities and people skills. There is disagreement about the merits of climate change science. There is an element of harking back to the good old days in government. There is strategic thinking about the electoral consequences of amending or opposing the Rudd government's ETS legislation.
But the rancour and hostility with which the internal debate has been conducted suggests that more is involved than these other factors. Some Liberal MPs have called the ructions a battle for the ideological soul of the Liberal Party. That sort of thinking is unhealthy for the party.
Traditionally Labor has been the more ideologically splintered of the major parties, combining, for instance, secular socialists and religious believers working side by side. It has had a tradition of strong discipline, based on a pledge signed by all party candidates to submit to the majority will of Caucus; partly to reflect the collective ethos and partly to hold together highly fractious factions. Even so Federal Labor has suffered three major splits, the last in the 1950s.
The Liberals on the other hand have always played down party discipline and emphasised the individuality and conscience of its parliamentarians. They have long boasted of a tradition of tolerating dissent to a greater extent than Labor. Statistics on crossing the floor in parliament collated by the Parliamentary Library support this view.
But an unspoken premise of Liberal internal operations has always been that the ideological divisions within the party, even between conservatives and liberals, were not as divisive as those found within Labor. Rather the public image that the Liberals have liked to project since Menzies has been one of practical men and women approaching each issue on its merits regardless of ideological presuppositions.
Both parties have been smug about their respective beliefs and the differences between them. Labor boasts about solidarity and the Liberals boast about individual conscience.
Lack of discipline and deep ideological differences are really testing the Liberals at the moment. While ideological differences are declining within Labor