An inopportune stoush with the military sank Labor's opportunity to further pursue Assistant Health Minister Fiona Nash over unexplained conflict of interest allegations, writes Barrie Cassidy.

Only Senator Stephen Conroy would feel bulletproof in a stoush with the military.

As a veteran of the media wars, he probably feels the defence forces are nowhere near as well armed as News Ltd.

Certainly the military, unlike the media, is constrained in what it can unleash when politicians insult them. Lieutenant General Angus Campbell has fought the Taliban with distinction. But when the Senator attacked him, he could do no more than register his disappointment and move on.

The Daily Telegraph, by comparison, faced with the prospect of media reforms, placed Conroy on the front page alongside the most despotic dictators of the 20th century, the likes of Stalin, Mao, Kim and Mugabe.

"These despots believe in controlling the press," the headline read.

Perhaps Conroy is shell-shocked after a bruising period in government, but to accuse the general of a cover-up over border security, and then refuse to apologise, is a big call for any politician; bigger still coming from the shadow minister for defence. In government or opposition, he has to live with the military.

One after another, Government ministers lined him up in Question Time.

Foreign Minister Julie Bishop said: "There is an unwritten rule ... that there be bipartisan support for our military, our troops, whether at home or abroad. That was shattered yesterday when ... he traduced the reputation of one of Australia's most distinguished military commanders for serving his country."

She called it "a despicable slur designed to dishonour an honourable man".

Then the Assistant Minister for Defence, Stuart Robert, got in on the act: "Our serving men and women deserve a lot better than this sort of grubby attack. If Senator Conroy were in the army, he would be peeling potatoes right about now."

Even the embattled Immigration Minister, Scott Morrison, was enjoying Parliament again, saying of the Opposition Leader, Bill Shorten, that his failure to force an apology was "an absolute disgrace".

More than making himself an easy target, Conroy by his actions threw Labor off its parliamentary tactics.

The fact that they were unable to further pursue Scott Morrison over Manus Island wasn't the real point. On that issue, the Opposition lacks conviction. They are simply too closely aligned with the structures that brought about the terrible events.

It is possible to support offshore processing, and it is possible to support turning back the boats, and still be sickened by what apparently happened on Manus Island.

Not only did a young man die that night, but scores of others were injured, all of them asylum seekers. Did staff attack the demonstrators with the sole purpose of bashing them up and teaching them a lesson? Such heavy-handed tactics would never be tolerated in any civilised society.

Yet the Opposition is constrained because Manus Island was their idea. What's more, the intolerable delays in processing and the lack of understanding between the Australian and Papua New Guinea governments over the fate of the asylum seekers is a brute of an issue that the Coalition inherited.

So that issue was never going to be adequately - and passionately - prosecuted by the Opposition.

The real issue that should have been advanced this week, had it not been for the Conroy distraction, was the conflict of interest allegations against the Assistant Health Minister, Fiona Nash.

The Minister now accepts she knew all about the links her chief of staff had with the junk food industry. Yet she told the Senate on February 11 that there were no links. That contradiction has never been explained.

But then based on the standard in the House on Wednesday, that's what passes as a defence these days.

Labor's Member for Ballarat, Catherine King, referred the Prime Minister to an answer he gave in Question Time on Monday, when he said Senator Nash's chief of staff was required to divest himself of a shareholding in his wife's business.

"I also refer to the Special Minister of State's statement in the Senate estimates last night (Tuesday) that Senator Nash's chief of staff was not required to divest his interest. Who misled the Parliament, the Prime Minister or the Special Minister of State?"

Abbott responded: "The short answer is neither."

The long answer did not attempt to disassemble the apparent contradiction. Then came another question.

King referred to Minister Nash's statement in Senate estimates that her chief of staff had complied with all the requirements to ensure there was no conflict of interest: "I also refer to the Prime Minister's statement in the House on Monday that he was required to divest himself of a shareholding and he was dilatory in doing so. Who is right, the Prime Minister or the Assistant Minister for Health?"

Abbott replied: "Happily, Madam Speaker, both."

There, fixed.

The issue got even stickier for the Government when the chief of staff was linked with the $16 million grant to Cadbury in Tasmania.

What role did he play, and did he benefit financially?

The questions were asked, eventually, but the answers are still elusive.

Barrie Cassidy is the presenter of the ABC program Insiders. View his full profile here.