Some of his victims never saw it coming. Some succumbed because there was no point in putting up a fight. Some - like Peter Dunne - pleaded innocence or argued their time was not up.

But the 2013 political year has turned out to be the Year of the Grim Reaper.

That was sadly the case with the death long before his time of Parekura Horomia, whose image in much of the Pakeha world as a bumbling and impossible to comprehend Maori Affairs Minister could not have been more inaccurate.

Fortunately, the Grim Reaper only struck figuratively after that. But the toll was heavy when it came to wrecking careers or setting them back with little or no hope of recovery.

The list of this year's losers reads thus: the dumping of two National Cabinet ministers; the resignation of one Leader of the Opposition and leader of the Labour Party; the effective ousting of one co-leader of one of the Government's support partners; ministerial resignations by the leaders of National's two other support partners; and the pending loss by one of his party's leadership next year and his standing down as a candidate at next year's election.

Seven of National's 59 MPs are so far quitting Parliament at the next election. They have been smart enough to read the writing on the wall that says they are unlikely to get promotion regardless of whether National wins. Whether through appointment to some Government board or other agency, they will be rewarded for putting the party first and avoiding giving the leader backbencher indigestion as he tries to find meaningful jobs for everyone.

At least two National electorate-based MPs are facing serious challenges to holding their seats.

Things are more tranquil on Labour's side of the parliamentary chamber, partly because there are high expectations inside caucus of getting a highly-ranked job if the party wins the election. Two MPs are going or have gone. Several others have been given the "you would be wise to quit because you are not going anywhere" message through demotion down the rankings.

A party's leadership is only immune for so long no matter how well it performs. Witness Pita Sharples' resignation as Maori Party co-leader. This year saw a semi-changing of the guard in New Zealand politics that had a major bearing on who takes out the title of Politician of the Year.

National did not have a bad year. The party's support in the polls remains at amazing levels - as does Key's personal rating as preferred prime minister.

Key, however, continued to be dogged by his handling of intelligence-related matters. No sooner had he finally put to bed new legislation covering the powers and responsibilities of the Security Intelligence Service and the Government Communications Security Bureau, than he was blindsided by the leaking of sensitive material in the US that raised serious questions about the level of monitoring being conducted by the American spy agencies and, crucially, New Zealand's connection to that activity through intelligence-sharing arrangements.

Because he is hamstrung by the convention that the operational activities of the two New Zealand intelligence agencies remain strictly confidential - or says he is - he can only give "trust me" assurances that those agencies are abiding by the law.

The problem is that the Kim Dotcom case and the subsequent Kitteridge report into the workings of the GCSB have largely neutered the trust-me defence.

It is Key's good fortune, however, that the raking over of such matters is peripheral to most people's lives and Key's efforts to escape from this particular bowl of molasses are watched more for entertainment than out of any great concern.

It is the equation that has the rate of economic growth on one side and the degree to which the Reserve Bank raises interest rates that will have an exponential-size impact on National's fortunes at the ballot box.

National's ability to have an influence on that equation is limited pretty much to the kind of fiscal policy it runs and whether it will hit its target of being back in surplus during the 2014-15 financial year. We will know more next Tuesday when Bill English presents the half-year fiscal update. If English meets the target - and at the same time presides over a reasonable period of sustained economic growth - that would make him a strong candidate for the title of Politician of the Year. But not yet.

Shane Jones showed during Labour's leadership primary in September that by and large he has the presence, intellect, temperament, skills - and not least the oratorical abilities - to do the job of prime minister. His positioning on his party's right means he is capable of reaching out to the centrist voters whom his party needs to win over to ensure a Labour-Greens coalition has a reasonable majority in Parliament and is not hostage to minor parties such as New Zealand First.

His preference for the blunt and direct means he is capable of penetrating the indifference of those non-voters whom Labour also needs to get to the polling stations.

What may well block Jones' aspirations in a future leadership contest is the pronounced shift of the wider Labour Party beyond the caucus to the left.

That shift, of course, has been to the huge advantage of the man who has to be judged the Politician of the Year if only by virtue of him seeing off the other challengers to gain the prestige of leading one of the two major parties.

Since taking over from David Shearer, David Cunliffe has not put a foot wrong - at least in a strategic sense.

An almost evangelical speech spelling out his attachment to traditional Labour principles was followed by what David Parker, Cunliffe's deputy, describes as a "stonking" by-election victory in Christchurch East.

Labour secured a far bigger majority than was expected by focusing its campaign tightly around local issues, holding a multitude of street-corner meetings and strenuous efforts to get identified Labour voters to the polling booths.

Cunliffe now has to somehow adapt those techniques to a national stage, lift his preferred prime minister ratings and raise Labour's share of the vote.

Somehow he has to do what Labour's two previous leaders failed to do - rebuild voter trust in Labour and then personify that trust in the manner John Key has done so naturally and successfully for National. No easy task.