British Labour leader Harold Wilson is responsible for an enduring political cliche: a week is a long time in politics. If Wilson were with us today he might concede a weekend is an eternity.

Bill Shorten, who turned in an indifferent first week of campaigning, can thank independent journalist Michael West for deflecting attention from a poor start to his bid to become the country’s 31st prime minister.

The government has been obliged to respond to reporting on the transfer of proceeds from a sale of water in the parched Murray-Darling Basin to a Cayman Islands-registered tax minimisation entity – Eastern Australian Irrigation (EAI). This distraction has upended the campaign’s second week.

What’s become known, inevitably, as "watergate" has come at an awkward moment for Scott Morrison in his efforts to put behind him an image of a conflicted and scandal-prone government

I have no idea about the rights and wrongs of what seems, on the face of it, an excessive payment for water trapped on properties in the basin, but circumstances surrounding a closed tender carry with them the odour of dying fish in the Menindee Lakes.

The fact that Energy and Resources Minister Angus Taylor was previously a director of Eastern Australia Agriculture, controlled by EAI, before he entered Parliament, and former agriculture and water minister Barnaby Joyce signed off on the deal, invite difficult questions for the government.

Morrison will have a particular reason to be disappointed over this latest turn of events, since it has shifted attention from his opponent’s shortcomings at a critical early moment in the campaign.

Shorten’s limitations as a nimble advocate for Labor’s cause were exposed in the campaign’s first week. His relative lack of popularity remains a drag on his party’s fortunes.

Labor insiders tell you that Shorten is a known quantity and his shortcomings as a communicator will have been factored into people’s calculations. That may be true, but in an election in which undecideds form an unusually large bloc of voters, the likeability issue cannot be discounted

What is most surprising about Shorten’s fumbling first week is that he has had 5½ years to prepare. He has led his party at one previous federal election in which he pushed the Coalition to the brink. He has seen off two opponents. Labor’s policies have been stress-tested, or at least they should have.

Yet his inability on occasions last week to respond simply and clearly to questions about the cost to the economy of Labor’s climate change policies, and whether reforms to superannuation will involve new taxes is, well, surprising.

History tells us political campaigns ebb and flow. Mistakes are inevitable. This is the nature of modern political campaigning in an era dominated by social media and a nano-second media cycle.

From the Coalition perspective, and in contrast to a Labor Party that is hearing footsteps, there are those in its senior ranks daring to hope all is not lost – although the water buyback issue will have dampened some of that enthusiasm.

“Scott exceeded expectations in the first week. Bill failed to meet them. We expected him to be more battle-ready," says a senior Liberal.

What is the case is that Labor’s reforms of capital gains, negative gearing, trusts and imputation credits, the so-called “retirees’ tax”, have made it a big target for a do-little Coalition.

Labor’s policies involve a lot of moving parts. These are not necessarily easy to explain – or defend. Unfairly, perhaps, this is the price it is paying for rolling out a complex suite of policies versus a policy-free-zone government on seminal issues like climate.

What is also relevant is that a Canberra parliamentary press gallery is doing its job in its efforts to hold Shorten, and now Morrison on the water issue, to account. In an election campaign one of the more contestable spaces lies between a journalist and a story that might embarrass one side or the other.

Shorten is finding that, unlike 2016 when he was not expected to prevail against Malcolm Turnbull, he is now being held to a higher standard given he is the front-runner. He better get used to it, and stiffen up his ability to handle difficult questions, or become an historical footnote like John Hewson.

Finally, polling and history cannot be overlooked. Latest polls are not necessarily conclusive for Labor, nor is history comforting for an opposition leader on the cusp.

At 53-47 per cent two-party preferred according to the latest Ipsos poll, the Coalition is well behind but not completely out of it. Significantly, the primary votes of the contenders have improved in latest polling.

Historically the Coalition tends to lift its primary vote over the course of an election whereas Labor’s slips back. In other words, Labor has less margin for error traditionally.

Then there is provenance.

On no occasion since World War II has a first-time Labor leader won government after his party went into opposition. In other words, Shorten would be defying history if he prevails.

In light of that, the alternative prime minister needs to bend history to his own ambitions, and exploit his opponent’s misfortunes. For Shorten, ‘watergate’ has come not a moment too soon.