He rejected Fairfax Media's defence of qualified privilege – a defence relating to reasonableness and public interest – because he found it was not reasonable for it to publish material with a defamatory meaning"to promote interest"in its stories.
The lack of reasonableness was enough for the defence to fail. In the case of theHerald,however,Justice White said the defence would have failed in any case because there was evidence of malice or"animus"behind the selection of the headline.
But the judge dismissed the lion's share of Mr Hockey's case,over the substantive articles promoted by the tweets and poster.
He found the May 2014 articles in theHerald,The Age,andThe Canberra Times,examining the activities of a Liberal Party fundraising body,the North Sydney Forum,were of"considerable public interest"and did not defame Mr Hockey by suggesting he was corrupt or took bribes.
This was so even though theHerald andThe Age – though notThe Canberra Times – used the"Treasurer for Sale"headline,which was found to be defamatory when stripped of its explanatory context on Twitter and on posters.
The Hockey decision marks the first time an Australian politician has sued successfully for defamation over a tweet,and it underscores some of the legal hazards of a medium which imposes a strict 140-character limit on missives.
On the same day as Justice White's ruling,a long-running defamation case brought by Liberal pollsters Mark Textor and Lynton Crosby against former federal Labor MP Mike Kelly over a tweet came to an abrupt end when Dr Kelly issued an apology.
He was represented by Bruce McClintock,SC,the same defamation barrister who acted for Mr Hockey in his action against Fairfax.
It was widely expected the Textor case would result in the country's first judgment on defamation by Twitter,but it was a low-key battle in the NSW District Court that took out the title.
Judge Michael Elkaim ruled in November 2013 that a schoolteacher was entitled to $105,000 in damages for a series of defamatory posts on Twitter and Facebook made to a small audience of followers.
It is the prospect of a wave of litigation against private individuals over social media posts,not posts by well-resourced media companies,that has some lawyers worried.
Sydney media law barrister Matthew Lewis said the vast majority of"ordinary Joes going about their business on social media don't have the same resources as those in the business of publishing".
"We could be in danger of seeing an influx of social media cases which are trivial … and which are completely disproportionate to what's at stake,"Mr Lewis said.
Uniform defamation laws passed across the country in 2005 were"outdated",he said,and"it's probably about time we revisited the[Defamation] Act,in light of recent developments overseas such as in the UK with a view to improving the current legislation".
He said the UK Defamation Act 2013,which came into force in January 2014,imposes a requirement of serious harm to weed out cases that are"trivial,which would amount to'bar room banter'."
Geoff Holland,a media law expert at the University of Technology,Sydney,said another contentious area was the liability of people for re-publishing defamatory material.
"People can be liable for what they retweet,so it's not just a case of liability of the person who has made the original tweet,"he said.
"While that's not an issue in this case,it's part of the bigger issue of why we need to revisit defamation law."
Associate Professor Rolph said Australian law-makers also needed to consider whether the status of a person should affect their entitlement to sue.
In the US,public figures including politicians need to show an allegedly defamatory publication is false and the publisher was motivated by"actual malice",a major impediment to bringing an action.
"Actual malice in the US Constitutional standard requires knowledge of the falsity of what you've published or potentially reckless indifference to the truth or falsity,"he said.
He said the US public figure doctrine would have"knocked[the Hockey case] out at the threshold".
This was not to say that Australia should adopt such a model,and many politicians"show a great deal of restraint and allow political debate to occur without ever suing". But any law reform process"necessarily needs to look at what other jurisdictions do".
The list of Australian politicians who have availed themselves of legal action to protect their reputations is long and includes Tony Abbott,Peter Costello,Bob Hawke and Sarah Hanson-Young –who settled her case in June againstZoo magazine over a doctored image.
Professor Andrew Kenyon,director of Melbourne Law School's Centre for Media and Communications Law,said developments in the UK and Canada had made it"harder for either politicians to sue or for people to sue over political communication".
A landmark High Court of Australia decision on qualified privilege,theLange case,found an implied freedom of political communication in the Constitution.
But media organisations have little success relying on this defence,or a statutory version. This is partly because they must show they acted reasonably,and decisions made under pressure in a newsroom are rarely judged to have met this standard.
Professor Kenyon said theLange equivalent in the UK,Reynolds,"has been stronger in practice"for media defendants.
In 2013,the UK went further and"introduced a statutory version that they said was picking up the strongest parts ofReynolds to protect public-interest speech,not just politics". Courts in Canada were"offering stronger protection as well",he said.
Changes to the law may not have altered the result in the Hockey case,and nor should any reform be a knee-jerk reaction to it. But any appeal by the parties may provide an opportunity for the High Court to revisit some of these broader issues.
The parties return to court on July 14 to argue about costs,injunctions and final orders.