The similarities extend to some familiar faces, including Malcolm Turnbull and Bill Shorten on the yes side and Tony Abbott and John Howard for no. Most of the other prominent faces are not as well-known, including the leaders of the opposing pressure groups, the Australian Christian Lobby and Australian Marriage Equality, which have campaigned relentlessly on the issue for years.

That much is recognisable, but there are noticeable differences for both ordinary citizens and curious political scientists. The turnout is unpredictable because participation is voluntary rather than compulsory. Furthermore, the options for citizens are much more limited as the campaign is channelled into just two choices – yes or no – or perhaps three, given that non-participation is a legal option. The enthusiastic and the half-hearted are thus bundled together in an unsatisfactory way when measuring likely responses.

These responses will slowly come in over almost two months rather than on a single polling day. This extended process may actually be popular among citizens given that pre-poll voting is growing for ordinary elections anyway.

But such a long response period is undoubtedly problematic for parties and groups trying to influence the outcome. How can they plan their campaign when they don't know when their targets will fill in and return the survey? Should they run an evenly paced campaign over the whole time period or concentrate on key times, such as the first and last weeks?

Conserving scarce resources would be easier if there was some collaboration and load-sharing between allies on the yes side, but that is not happening. The idea of one, big, bipartisan campaign was rejected because traditional opponents like Turnbull, especially, and Shorten were unwilling to appear together on the same platform. Surely such bipartisanship would be a persuasive sign of common ground between erstwhile opponents.

Yet any such thinking was trumped by the appeal of conservative political colleagues sticking together in a freshly minted organisation with the bland name: "Libs and Nats for Yes." The name is descriptive but uninspiring. Even calling it "liberals and conservatives for same-sex marriage" would have reached out to people of similar philosophical persuasion who support One Nation or the Australian Conservatives rather than the Coalition.

Presumably, these Liberals and Nationals (self-described as many party elders and some current MPs) feared that any joint campaign with Labor and other yes groups could exacerbate conflict within the Coalition party room by ceding control of the tenor and style of their conservative yes messaging.

The two separate yes campaigns certainly feel very different. The Liberals and Nationals have a careful, party-based approach, with clear boundaries and moderate arguments. Labor, while still careful, has been much more willing to stand side-by-side with social-movement activists in the long-running marriage-equality campaign.

Turnbull and his yes allies faced a tricky situation because many of their past and present parliamentary colleagues are firmly entrenched among the no advocates in the Coalition for Marriage. If they wished to criticise the controversial Coalition for Marriage television campaign, for instance, they ran the risk of a public brawl with cabinet colleagues like Barnaby Joyce.

About one-quarter to a third of voters now support a minor party or independent. This time, however, minor parties and independents are effectively written out of the script. Crossbenchers have expressed their opinions, and will have a final parliamentary vote when and if the time comes, but are not doing much campaigning, conserving their limited funds for the next election in 2019.

In other ways, however, the campaign is more broadly based than usual and has drawn in many non-political organisations, such as the professional bodies for doctors and lawyers, in the process generating internal fights with some of their dissenting members about their right to take an official, collective position.

Some of these big organisations, like corporations and churches, have been part of the same-sex-marriage controversy for some time now, regularly pitting archbishops against business leaders.

The campaign's reach continues to grow, however. Drawing on their experience in the reconciliation and anti-racism campaigns, sports organisations like the National Rugby League, supported by sports journalists, are speaking out, too.

The campaign's first days have been a strange mixture of persuasive human stories, bland, low-temperature campaigning, bad tempers and allegations of hurtful personal attacks. This week's Fairfax Ipsos poll results, which seem to show the yes "vote" well ahead, must have both sides of the campaign thinking about whether to make changes.

The yes-campaign leadership probably feels more relaxed and comfortable, and inclined to a business-as-usual approach while not dropping its guard.

The no campaign may dismiss the survey results as unrepresentative, reinforcing its preferred position as the underdog. A low turnout may still be its saviour; therefore, a lower-key campaign may suit its purposes. But does it have a plan B with a new direction, or must it just redouble its efforts?

There will no doubt be twists and turns before time is called on this campaign. The key question is whether the no side, now trailing, can fight back with new strategies and tactics. The ball remains in its court.

John Warhurst is an emeritus professor of political science at the Australian National University.