In politics, MPs who leave under a cloud are often consoled by the saying "as one door closes another opens". For a very rare few, that open door is the same one they left from.

Since the police decision not to lay charges against former Labour MP Darren Hughes, it appears likely he will be one of those few should he decide to return to Parliament.

There is an unwritten operations manual on how such things should be handled. In reality, human nature comes into play.

The ability to weather a storm depends on a variety of factors beyond the simple facts of a case.

They include the party's leadership at the time, the person's own abilities and the stage of their political career. But the main one seems to be their credit in the popularity bank.

Former Labour president Mike Williams said Mr Hughes' popularity was what would give him a second chance.

"Darren is very, very popular within the Labour Party - extremely popular - and within the caucus. He was funny, intelligent and didn't appear to belong to any factions. He was everybody's favourite.

"I don't think Richard Worth occupied anything like that status in the National Party ... [he] had almost no support within the National Party caucus. I think they were probably pleased to see the back of him."

The need to have support among the party was evident in the case of David Benson-Pope in 2005.

Mr Benson-Pope was reinstated to his ministerial roles after police decided not to lay charges over claims he stuffed tennis balls into boys' mouths as a teacher in the 1980s.

But the Labour Party was not so forgiving - he lost his seat in a selection battle against Clare Curran.

Mr Williams said the signals from Labour were unequivocal. Mr Hughes would not return this election but could easily do so in 2014.

"He's 33. He'd be 36 or 37 then. He's still quite young and he has a lot of support in the Labour Party.

"There's also a kind of fair-mindedness about Kiwis that says, 'Yes, you've stuffed up, but you can have another go'."

One obvious comparison for Mr Hughes was Colin Moyle, who resigned in 1977 after then Prime Minister Robert Muldoon accused him of being investigated for homosexuality. Moyle returned to Parliament in 1981 and became a minister in the Lange Labour Government.

Former National Party staffer and blogger David Farrar also said popularity was a big factor. Age was another. Although Dover Samuels and Mr Worth were never charged, both were at the stage of being gently elbowed out of politics anyway.

Mr Farrar points to the contrast in treatment of former Alliance MP Phillida Bunkle and Labour minister Marian Hobbs as another example of popularity playing its part. Although both resigned their ministerial posts over investigations into their claims for the accommodation allowance, Ms Hobbs was later reinstated as minister and Bunkle was not.

"Hobbs was well liked but Bunkle had rankled a few people. So that was a clear sign that there is never a consistency to the rules."

Mr Farrar pointed out that Mr Hughes was also helped by his political opponents resisting using his situation as ammunition.

"The Worth case was highly politicised. National has been very disciplined - and it's easy because they like Darren - not to make hay of it and do cracks or snarky press releases. When Worth was in the gun, Phil Goff led the charge."

Mr Samuels doubted Mr Hughes would face the same problem he had in getting reinstated because of his relationship with the party leadership.

"In my case there were other factors, in that I was too much of a male. I was too much like JT [John Tamihere] and I think the inner circle at the time saw it as an opportunity for them to move Dover Samuels sideways instead of putting him back where he should have been."

His advice to others hasn't changed: If you've done no wrong, don't resign in the first place.

"The difference is Darren was asked to resign and he resigned. I was asked to resign and I told them to get stuffed. I would encourage Darren to apply to be reinstated and given a high list ranking.

"In fact, it would be prudent for Phil Goff and the president to approach Darren and say: 'You've been cleared and you will be reinstated through the party's democratic process'. That way there is no possibility of further prejudices against him now that this matter has been cleared up."

On Radio NZ this week, another former MP who found himself on the wrong side of his leaders' affections, John Tamihere, said the difference between Mr Hughes and others was Mr Hughes' natural ebullience - or, as Mr Tamihere put it, his ability to "ingratiate himself" with a broad range of people.

However, Mr Farrar was not so sure Mr Hughes would not face that flak later, if he returned. He points out police had not "cleared" Mr Hughes - they had found there was insufficient evidence to base charges on. Similarly, police had not dismissed the complaint as vexatious or a waste of police time.

"So if you do want to carry on there will be a lot of pressure to clear up what's happened. Yes, he can return and will be able to be a senior spokesperson. Will it be forgotten, though? Probably not. It will remain an issue for some people."

With the exception of Mr Samuels, all those spoken to believed Mr Hughes should take some time out, not so much as penance but to sort himself out. Some said his experience was a salutary lesson about the perils of entering Parliament at a young age and having to cope with growing as a human being while under the scrutiny public life affords.

Even his friends in Labour believe some time out will serve him well and return him as a stronger person.

If he does return, he is likely to do so having learned similar lessons to Mr Moyle, who said on his return in 1981 his experience had made him "a sadder and wiser person".