No surprise that tweets during the leaders' debate on Sunday peaked at the discussion on same-sex marriage towards the end of the event. Nor that channels Seven, Nine and Ten declined to show it on their main channels.

There has been so much national politics in the media over the past three years it is understandable why a clear majority of voters watched something other than the Kevin Rudd v Tony Abbott contest and did not exhibit much excitement when it was reported that the Prime Minister had promised that a re-elected Labor government would introduce a same-sex marriage bill within its “first 100 days”.

ABC managing director Mark Scott has a habit of entering into a state of denial when considered criticism is made about a lack of pluralism within the public broadcaster. However, the media story of Sunday's event turned on the fact that the umpire was Sky News' David Speers, who did well in a difficult environment.

The ABC did the production for the debate. But the host was the National Press Club and it entered into discussions with the ALP (George Wright) and Liberal Party (Brian Loughnane) directors as to who should compere. Speers was the chosen one. Which suggests that either one or both of the main parties did not want to entrust this crucial role to an ABC presenter.

Speers had a special insight into the issues which might be raised. On Sunday afternoon, Sky News predicted same-sex marriage might come up. During an appearance on a Sky News panel, just before the debate, News Limited journalist Malcolm Farr suggested Rudd would commit Labor to introducing same-sex marriage legislation.

And so it came to pass. But only just. When the Prime Minister had not raised the issue in the main part of the debate, Speers threw a final question on the topic. Rudd stated how he had changed his position and now supported the concept. Abbott did not directly address the issue but said that it would not be a priority for an incoming Coalition government.

Most journalists and commentators welcomed Rudd's stance, considering it as both a progressive and positive contribution to the political debate. Maybe. But maybe Abbott's approach is more politically cautious.

In his book In God They Trust? The Religious Beliefs of Australian Prime Ministers 1901-2013, Roy Williams commented that in 2007 Rudd brought into Labor's fold hundreds of thousands of “lower income Christians of all denominations – but especially Protestants”. Williams wrote that one of the key reasons for Labor's electoral decline over the past three years has been “the re-alienation of this important demographic, especially in Rudd's paroxetine sale home state of Queensland”.

On Lateline last Friday, the former ALP Queensland senator John Black criticised the inconsistencies in Labor's campaign north of the Tweed River. He commented that the ALP seems “to lack a coherent focus on the one demographic group – and the key group for Kevin Rudd [in 2007] was young working-class families in the outer suburbs, many of whom go to church and believe in God”. Black added that he has not seen “Kevin Rudd talking to those people a lot during the course of this campaign”.

It is unlikely that evangelical Christians or mainstream Catholics will be impressed by Rudd's conversion to same-sex marriage. The same is true for Muslims who are an increasing influence in Western Sydney. Abbott's enthusiastic reception in Lidcombe last week, at the end of Ramadan, was under-reported in the media. It should have been of concern to Labor.

For almost four years, Labor has been convinced that Abbott's social conservatism is a turn-off in the electorate. This view was unequivocally ennunciated by Labor campaign strategist Bruce Hawker in an article which he wrote for The Daily Telegraph on February 2. Hawker described Abbott as “Labor's biggest asset” and claimed that the Liberal Party leader “has managed to typecast himself as a conservative with decidedly mid-20th century values”.

If Labor prevails on September 7, Hawker may be proved correct. If not, it would seem that he has underestimated the social conservatism of suburban and regional Australia.

At the weekend, Labor disendorsed Ken Robertson, its candidate for Kennedy. Robertson had told The Courier Mail that he hoped “Australia never had to suffer his [Abbott's] Catholicism … because he's a very, very bigoted person”. Though similar comments have been made before, opinion polls indicate that much of the electorate does not mind the Liberal Party leader's social conservatism – even if much of twitterdom does.

Gerard Henderson is executive director of the Sydney Institute.