Throughout his first year as opposition leader, Bill Shorten has adopted a “small target” strategy, which has been the subject of considerable criticism. “Missing in action” has been among the kinder phrases used.

The criticism has only intensified with Shorten’s endorsement of the Abbott government’s commitment of troops to a new Iraq war, and Labor’s support for a slightly amended version of the government’s anti-terror laws, explicitly sold as reducing our freedom.

Much of this criticism misses the point, harking back to a largely imaginary past in which the big issues of the day were thrashed out in parliament, and particularly in the presentation of alternative policy platforms by party leaders.

In reality, some version of the small target strategy is effectively forced on the main opposition party by the way in which our political system and media now operate. This in turn means that serious criticism of government policy must come from elsewhere.

The first problem faced by an opposition leader who might wish to break away from the small target strategy is that of media invisibility. A visit to Shorten’s website reveals a near-daily output of speeches, press releases and media interviews. The vast majority of these go virtually unreported (except in the case of media interviews, which are routinely ignored by rival outlets).

Next there’s the asymmetry between the resources available to the opposition and those available to the government. This ensures that any substantive policy proposal put forward by the opposition will be subject to merciless criticism (amplified in Labor’s case by fact-free attacks from the Murdoch press). This, combined with the lack of media interest in any serious issue creates strong pressure to make no new commitments until the election campaign is underway.

There is one issue faced by an opposition party, namely whether to walk away from controversial policies it adopted in government, as the LNP did with WorkChoices after 2007. On the whole, Shorten has not done too badly on this score: Labor has retained its commitment to carbon pricing, the mining tax, the Gonski reforms and the NDIS. The party is confused and vacillating on the asylum-seeker issue, but that was just as true in government.

The biggest problem though is the general unpopularity of politicians, summed up in the maxim “oppositions don’t win elections, governments lose them”. This unpopularity, which has grown over time as politics has become professionalised and poll-driven, pushes opposition parties towards a strategy of risk-avoidance and negativity.

The success of the deeply unpopular Tony Abbott, running almost entirely on distaste for a chaotic Labor government, has only reinforced this pressure. The upshot is that elections become referendums on the performance of the government. The opposition wins, if it does, not because of any positive merits, but because, by definition, it is not the government.

And the process feeds on itself. The less that the parties engage in an issue, the greater the alienation of the public from the political process, and the greater the payoff to negativity. In these circumstances, the adoption of a small target strategy is the obvious approach to political opposition. Governments, faced with the necessity of actually doing things, do not have this strategic choice, though that did not stop the Abbott government from attempting it during its first few months in office.

The re-emergence of war and terrorism as major political issues threatens to derail Shorten’s small target strategy. The decision to participate in our third Iraq war in 20 years, is deeply problematic, to put it mildly.

Not only are we dealing with an enemy created by the previous war against Saddam Hussein, but the arguments about the monstrous evil represented by that enemy are almost exactly the same as those made about Saddam a decade ago. Even granting their validity, who is to say that a new war, with the inevitable civilian “collateral damage”, will not unleash even greater demons?

Yet the political imperative to line up with the government has proved overwhelming. Labor correctly opposed the 2003 invasion, but scored no political credit. The politics of opposing a call to arms from Barack Obama, in the context of domestic terrorist threats, have proved too hard for Labor to consider.

In the absence of any real debate between the major parties, the only effective criticism of government policy comes from forces outside the traditional political process: minor parties, activist groups of various kinds and public mobilisation. These forces have derailed some of the government’s attempts to reset the terms of political debate over issues like social justice and environmental policies, and have achieved at least some limits on the near-boundless expansion of police powers sought in recent weeks.

The need for a public debate over our response to the new Iraq war and to renewed threats of terrorism is obvious. But the days when the House of Representatives was the natural forum for such a debate, and when the two main political parties were the obvious protagonists are gone, for good or ill.