Tony Abbott, the current leader of Australia’s main conservative party, once crudely dismissed climate change, but after he became the party boss, even he embraced the need to bring down emissions. Instead of cap and trade, though, he argued for industry friendly taxpayer-funded incentives to cut carbon.

Malcolm Turnbull, Abbott’s predecessor, supported cap and trade, as did his predecessor. “On climate,” Turnbull told me, “there has been an assault on the science, and it has had an impact, but not to the point of the center-right parties adopting a ‘climate-change-science-is-bunk’ platform the way the G.O.P. appears to have done.”

Conservatives in Australia and New Zealand have also long accepted single-payer national health care systems. The Labor Party ruled New Zealand from 1999 to 2008, when it was replaced by the conservative National Party. During Labor’s tenure, it passed legislation legalizing civil unions, giving prostitutes the same health and safety protections as other workers, and extending income subsidies for families with children, noted Jon Johansson, a political scientist at Victoria University of Wellington. While these moves were resisted by conservatives when in opposition, he said, they have “not tried to repeal any of them” now that they are in power.