It’s the election rumour that won’t go away.

Crikey readers asked us back in April to investigate whether broadcaster Derryn Hinch, who’s spent two stints in jail and five months under home detention for breaching suppression orders, is eligible to run for the Senate. Our investigations suggested he is. Others have also had a squiz at it and reported the same thing. But widespread suggestions that he isn’t are still around, if you’re looking.

Last night at a panel at the University of Melbourne, no less a political heavyweight than ABC Insider’s Barrie Cassidy said there was a good chance Hinch would be elected in Victoria, and “he’s ineligible”.

 “He’s ineligible. He’s been convicted of an offence that carries with it more than a year in jail, and that makes him ineligible. And yet he could win the seat and if he does he’s then susceptible to a High Court challenge. It’ll win, that challenge would succeed. The whole of Victoria could go back to elect the 12 senators again. It happened in Western Australia it could happen here.”

Hinch is trying to take it in stride. “I must be a serious chance [if] opponents are starting to spread this canard.”

He says the charge that he’s ineligible has floated up on the ABC this week, to his frustration. “You reckon I wouldn’t have checked that out? With lawyers and the clerk of the Senate?”

The confusion arises due to the fact that Section 44 of the constitution does mention criminal convictions as a factor in eligibility. But on most readings, that’s not a permanent condition. The wording is that someone is ineligible if he or she is “attainted of treason, or has been convicted and is under sentence, or subject to be sentenced, for any offence punishable under the law of the Commonwealth or of a State by imprisonment for one year or longer”.

This is taken to mean that a candidate is ineligible if he or she has been convicted and under sentence for serious crime (with possible imprisonment of one year or longer), not to mean he or she is ineligible if convicted or under sentence. Separate, more severe restrictions apply to those convicted of treason, and those convicted of various types of electoral fraud or bribery are ineligible for two years after serving their sentence, but neither of these conditions apply to Hinch.

The University of New South Wales Dean of Law George Williams, a leading constitutional expert, endorsed that interpretation this morning: “Section 44 disqualifies a person when they are currently under sentence for an offence punishable by one year or more imprisonment. Hinch is no longer under sentence, having served his time.”

Laureate Professor Emeritus Cheryl Saunders, another constitutional expert from the University of Melbourne, agrees. “Your conclusion is right — not a problem if he’s not currently under sentence.”

But some disagree. Cassidy told Crikey this morning the constitution was “sufficiently ambiguous as to make a challenge to the High Court likely”. “It’s complicated but it swings on the word ‘and’ in the clause and how that is interpreted.” He expanded on the issue on 774 Melbourne with Jon Faine this morning. “The constitution is a little ambiguous on this … as to whether or not if you’re convicted but not sentenced to a year, or whether you’re just convicted of an offence of that nature that makes you ineligible …” (Of course, if candidates are ineligible only while actively under sentence, the maximum sentence of the crime they are convicted under wouldn’t matter for those who’ve served their time).

In 1987, the High Court dealt with a case that looked at whether Senator Robert Wood, elected that year, should be ruled ineligible for a 1972 conviction he had been jailed for. The High Court ruled in Wood’s favour, with the judgement stating:

“The disqualification operates on a person who has been convicted of an offence punishable by imprisonment for one year or more and is under sentence or subject to be sentenced for that offence. The references to conviction and sentence are clearly conjunctive, although counsel for the petitioner argued otherwise. This is so as a matter of construction of the language used in s.44(ii). And it is apparent that it was the intention of the framers of the Constitution that the disqualification under this paragraph should operate only while the person was under sentence.”

Many states have far harsher provisions preventing former criminals from entering parliament (Western Australia bans all those with criminal convictions of serving for life), but according to this informative Parliamentary Library briefing on candidate eligibility and criminality, the constitution is fairly lax on the issue.

Previous federal politicians to be elected despite serving time in prison include war-time Labor prime minister John Curtin, who was charged during World War I with failure to enlist and convicted while he was interstate to three months in jail. He spent three days in jail, but the prosecution ended up being withdrawn. Neo-Nazi Jack van Tongeren, who spent more than a decade in jail for a run of serious crimes, said in 2003 he wanted to run in the 2004 federal election. That caused an outcry, but despite WA’s attorney-general calling for the federal eligibility rules to be tightened up, the constitution, which the ABC at the time said guaranteed his right to run, wasn’t changed.

While Cassidy obviously rates Hinch’s chances, opinions do vary. Dr Nick Economou, a senior lecturer with Monash University, has been quoted saying Hinch is unlikely to get quota. Crikey’s William Bowe agrees, though says it’s very hard to gauge for sure.

For the record, Hinch tells us he’s also renounced his New Zealand citizenship, so that won’t be a problem under section 44 either. He’s been an Australian citizen since 1980.