When political parties are decimated in an election they run the risk of being taken over by a Manchurian Candidate. Although the book and movies are about political assassins, the main thrust is about infiltration.
Political parties that have lost MPs and more importantly their volunteers and support base run the risk of infiltration by enthusiastic volunteers that could be making the long play in their political career. Getting involved at a time when the party desperately needs volunteers and workers, helping re-build, gaining influence and recognition and ultimately gaining selection.
Labour is exposed just as National was in 2002. At a time when you know convincingly that all your old ideas have been comprehensively rejected someone coming along with new ideas and enthusiasm can be welcomed to the fold like almost like a drunk finding a half drunk bottle in the bottom of the cupboard. The Act party is also likewise exposed. These infiltrators, with patience can exert considerable long term influence on political parties. It is when they are at their lowest that the parties are susceptible. There is literally no one to challenge the authenticity of new members or volunteers.
Of course there could also be a cynical, ultra-machiavellian play by political operatives to get their candidate elected to the leadership, organising and orchestrating mass endorsement, rolling over the top of the other ill-prepared contenders with mass acclamation of the ascendency of the Manchurian Candidate.
Both scenarios help move a party across the political spectrum, from one position to another, one modus takes time the other altogether more immediate.
Of course I could also be charged with fomenting happy mischief, but then again the evidence is all there before you.
