There’s no doubt about the outcome of the French parliamentary elections, which conclude on Sunday. President Sarkozy’s centre-right UMP will win a huge majority, probably more than 400 out of the 577 seats.

Sarkozy’s opponents are in disarray, with the main opposition party, the Socialists, tearing itself apart over how far to go in forming a broad front with other parties.

Defeated presidential candidate Segolene Royal called openly for an alliance with centrist Francois Bayrou, whose Democratic Movement received 7.6% of the vote in the first round. She clearly has in mind the sort of centre-left coalition that Romani Prodi has successfully forged in Italy.

But the Socialist establishment — including party secretary Francois Hollande, who happens to be her de facto husband — have rejected Royal’s approach, determined to maintain their doctrinal purity even if it consigns them to irrelevance for another decade.

Bayrou has also rejected closer alliance with the Socialists, and his party looks like being all but wiped out; most of his parliamentary colleagues have formed a new group, the New Centre, which is aligned with the UMP.

If this all seems very foreign to the Australian experience, there’s a good reason. The choices that in most democracies get made out in the open — liberals having to decide whether to work with conservatives or social democrats, and socialists having to decide how far to reach out to the middle class — have been driven underground by the way our parties have developed.

The Australian party system was formed a century ago, when liberals and conservatives decided to sink their differences and join forces to oppose the perceived threat of socialism. Despite a few half-hearted attempts to break apart (most recently with the Australian Democrats), they’re still together.

The obsessive attention, on both sides, to the role of trade unions in the current election campaign is a legacy of that decision. Much has changed in a hundred years, but Australia seems stuck with its archaic and inflexible class-based parties.